Glossary |
3D cache
To improve the overall performance of 3D data applications, data need to be pre-processed before they are used. That is, hierarchical cache needs to be created from the data. For example: to pre-process image data is to simplify the image data into a set of images with different resolutions. A series of images with different resolutions can be created through resampling. Every layer is stored separately. A corresponding spatial indexing mechanism is also created to improve the speed of displaying images when a user zooms in and out. The process of pre-processing vector, image, terrain, or model data and creating a hierarchical cache is called generating 3D cache.
3D Data
3D data include vector data, maps, images, terrain data, models, KML data, etc. Currently, SuperMap iServer not only supports publishing these source data, but also supports publishing cached 3D data generating from pre-processing these source data. The data are split in levels and tiles during the pre-processing for caching. For KML data, it corresponds to a KML dataset. The supported 3D cache data include: maps, images, terrain data, models, and KML data.
3D model cache data (SCV, SCM)
The recommended data format is *.scv which replaces the original *.scm format.
After cache is generated from 3D model data, a configuration file *.scv and an index file *.dat (former *.scm and *.index) are also contained besides a *.sgm model file. *.scv is in a plain-code format, and is the cache configuration file of 3D model data. SuperMap loads cached 3D model data via the *.scv file.
Adjacent Node
Adjacent nodes of a specific node on a network are all the neighboring points connected to the specific node.
Allocation
In an allocation analysis, the resource supply and demand in the real world are simulated, and the resource is allocated from supply locations to demand locations (including edges and nodes) based on impedance settings on the network, so that the supply locations can provide resources to the demand locations in the most cost-effective way. The demand location (edge or node) that can be reached from the center point with the least impedance gets the resource first; then the demand location (edge or node) with the second least impedance gets the resource; and so on. This process goes on till all the resources at the center are allocated.
Barrier
The node/edge that prohibits passing on the network. For example, in a transportation network, if a street does not allow passing due to maintenance, this street (edge) can be set as a barrier.
BBOX (Bounding Box)
Bounding box. A series of (2~8) values that represent the upper and lower boundaries of a 1D, 2D, 3D, or hyper dimensional feature.
Buffer
Buffer analysis is a basic GIS spatial analysis. A buffer is in fact a proximate area with a certain width created around a base spatial feature. Buffer analysis can be used in applications such as determining the extent for widening a street, determining the region of influence of a radiation source, etc.
capabilities XML
Service-level metadata for describing available operations and contents of a service instance.
Cached Terrain Data
To cache terrain data, the data are sliced into tile data which are named based on certain rules and saved in the corresponding cache folder. In the mean time, the system will generate an index file in the *.sct format under the root cache directory. The tile data are usually in the PNG, GIF, or JPG format. The *.sct file is the configuration file of the cached terrain, and is generated when SuperMap creates the cache directory for storing massive terrain data (DEM and Grid elevation data). The *.sct file describes the generated cache in details. It records information such as the cache path, the geographical extent of the data, the layer count, the tile size, etc. The tile data and the configuration file *.sct together constitute the image cache data. When the user loads cached terrain data in a 3D environment, the terrain data can be loaded via the corresponding index file of the cached terrain. An application program loads cached terrain data according to a specified *.sct file. Thus using terrain cache can greatly improve the efficiency of loading and viewing massive terrain data.
Cached image data
The method to cache image data is to first slice the data into tile data, and then save the tile data to corresponding cache folders after naming them according to some rules. In the mean time, the system will generate an index file in *.sci3d format under the root cache directory. The tile data are usually in the PNG, GIF, or JPG format. The *.sci3d file records cache information for the image data, i.e., it is the configuration index file of the data files of the image cache. The *.sci3d file is a text file, and is generated when SuperMap creates a cache directory for massive image data (image files in the *.bmp, *.gif, *.jpg, *.png, or *.tiff format). This file describes the generated cache in details including the path of the cache, the geographical extent of the data, the number of levels, the tile size, etc. The tile data and the configuration file *.sci3d together form the image cache data. When users add cached image data in a 3D environment, they can load the index file of the image cache to load the corresponding cached data. In this way, the efficiency of loading and viewing massive image data can be greatly improved.
Center
A center is a discrete facility located at a node on a network, with the ability to receive or provide resources. For example, there is education resources in a school and students must go to school to study; a retail warehouse stores commodities needed by retailers, and the commodities are sent to the retailers every day. In these cases, the facilities that have some resources stored and can provide services to people can be considered as centers on the network. A center in fact is a node on a network. A node can be assigned as a center via a field during an analysis process.
CGI (Common Gateway Interface)
The full name of CGI is "Common Gateway Interface". CGI serves as a standard for determining the method of communication between a Web server and an outside program, ensuring that the outside program can generate HTML, images, or other content. The general CGI programming languages include Perl, C, and PHP.
Clip
Clip is an operation in which a specific part of a dataset is extracted with a clipping dataset. The clipping dataset (the second dataset) must be of the region type. The dataset to be clipped (the first dataset) can be of the point, line, region, route, or CAD type. In the dataset to be clipped, only the objects that fall within the polygons in the clipping dataset are exported to the result dataset.
Closest Facility
Given an event and a set of facilities on a network, a closest facility analysis is to find one or more facilities that can be reached from the event with the least cost. The analysis result also includes the optimal paths from the event to the closest facility (or facilities). For example, when a vehicle is running out of gas, it needs to find the closest gas station; when someone gets sick suddenly, he/she needs to find the closest emergency center to get help.
Cluster Service
A cluster service is a service in which iServer services are registered on a cluster server and a single client view is provided. Once a service request arrives on the cluster server, the cluster server utilizes the cluster technology to assign the iServer service. The user does not know specifically which GIS servers are providing the service.
A cluster service provides the cluster service capability in the form of a Rest service. It retrieves service information about the available GIS services in the corresponding GIS application (or a lower-level cluster service) from a listener. A cluster service contains a load balancing object which uses a specified algorithm to find the available GIS service with the minimum load, in order to assign tasks in a balanced fashion for a request from a cluster client.
Cluster System
A cluster system is a computer system of highly transparent and scalable GIS services. Such a system as a whole provides clients with GIS services, while inside the cluster system the GIS services provided in a GIS application are managed and assigned through a cluster service.
Cluster Application
In SuperMap iServer, a cluster application is an application which can provide GIS services itself and can also use the GIS service capability in the cluster. Every SuperMap iServer server can be used as a cluster application.
Clustering in process
Adopt a cluster mechanism in a SuperMap iServer service in order to improve the performance and efficiency of concurrent accesses.
Connected Edge
A connected edge is an edge that can be reached from a selected node on a network. The figure below shows a connected edge analysis result with a query level of 2. (The query level is the level of connected edges to be queried for. The edges immediately connected to the analysis node are first-level connected edges; along the analysis direction, the edges directly connected to the first-level nodes are second-level connected edges; similarly, connected edges on the third level, the fourth level, and so on, can all be obtained. The search will stop when the level of connected edges exceeds the prescribed parameter.)
Connected Node
A connected node is a node that can be reached from a selected node on a network. The figure below shows a connected node analysis result with a query level of 2. (The query level is the level of connected nodes to be queried for. The nodes connected to the analysis node with a single edge are first-level nodes; along the analysis direction, the nodes connected to the first-level nodes with a single edge are second-level nodes; similarly, nodes on the third level, the fourth level, and so on, can all be obtained. The search will stop when the level of connected nodes exceeds the prescribed parameter. When the "Query level" is set to 1, the connected node analysis result will be the same as an adjacent node analysis result.)
Connectivity
Determine whether two specific nodes on a network are connected.
Config
The configuration file of a 3D dataset. Different 3D data have different configuration files. The output format of the config resource depends on the type of the 3D data. When a configuration file is being retrieved, <format> is the extension of the configuration file corresponding to the 3D data type. The output format can also be null (the corresponding default configuration file is returned in this case). The configuration file type can be *.sci3d, *.sct, *.scm, etc. When the 3D data are cached 3D model data (SGM data), the level parameter must also be passed via the URI, because every cache level of the model data has a data configuration file.
CQL (Common Catalog Query Language)
Common Catalog Query Language. A query language similar to SQL. It is simple and can mix commands and parameters.
Critical Edge
A critical edge is an edge that must be passed when traveling from a starting node and an ending node.
Critical Node
A critical node is a node that must be passed when traveling from a starting node and an ending node.
CRS (Coordinate Reference System)
A CRS uses the Earth as a reference, and is constituted with a coordinate system and a datum.
DataSource
A datasource is a set of datasets composed of various types of datasets (such as point data, line data, region data, TIN, GRID, and NetWork). A datasource can contain one or more datasets of different types, and can also store vector datasets and grid datasets at the same time. SuperMap provides a number of datasource types: file datasource, SQL+ datasource, Oracle datasource, SQL datasource, and Oracle Spatial datasource.
DataSet
A dataset is a set of data of the same type. Dataset types include: point dataset, line dataset, region dataset, CAD dataset, text dataset, route dataset, attribute dataset, ECW dataset, and MrSID dataset. Multiple datasets can share the same datasource.
DCP
Distributed Computing Platform
Domain Spatial Service
There are two types of spatial services in SuperMap iServer: one type is general spatial services (GSS) provided by SuperMap iServer itself, including MapService, DataService, NetworkAnalystService, RealspaceService, etc; the other type is domain spatial information services (DSS) which users build by themselves for processing spatial information based on special business logics of their domains, such as a map service for wind direction symbols applied in the meteorology industry.
Domain spatial services are used to describe services related to GIS applications in specific industries. Users can add their own business logics through second development or configuration of general spatial services. In this way, spatial services that meet the special requirements of a certain industry can be created. Thus the general spatial services can be reused in specific domains on multiple levels.
DTD (Document Type Definition)
Document Type Definition. DTD is part of the XML 1.0 standard. It constitutes part of an XML file as its verification mechanism. It defines the element schema as well as the element tags and attributes of the XML file.
Edge
An edge is a link in a network. An edge connects to other edges via nodes, and every edge is connected to two nodes. Edges can be used to represent components of a network in the real world, such as highways and railways of a transportation network, transmission lines of an electricity grid, and rivers in a hydrologic network. The connections between edges have a topological structure. In SuperMap, all edges are stored in a network dataset.
EPSG (European Petroleum Survey Group)
The European Petroleum Survey Group.
Erase
Erase is an operation in which the part in a dataset that overlaps with an erasing dataset is erased. The erasing dataset (the second dataset) must be of the region type. The dataset to be erased (the first dataset) can be of the point, line, or region type. The polygons in the erasing dataset define the erasing regions. In the dataset to be erased, the features that fall within these polygon regions will be erased, while the features outside of the polygon regions will be exported to the result dataset. The Erase operation is the opposite of the Clip operation.
Failure transfer
Failure transfer is a critical technology for achieving the fault tolerance capability in a cluster. When one node failed, another node in the cluster will be selected, and the processing will go on and not be terminated. Transferring to another node can be achieved by direct coding, or by automatically and transparently routing to another server through the underlying platform.
Feature
The representation of a definitive spatial entity and its attribute information.
Filter
Filter is a language implemented in XML. It is very suitable for a distributed system. In a WFS service, the <Filter> element is used to set a query constriction, both spatial and non-spatial. The constriction is used to filter the result of a GetFeature operation, i.e., a feature result set. The methods to filter are the operators defined by Filter. Filter defines three types of operators: Spatial operators, Comparison operators, and Logical operators.
Generic Spatial Service
Generic Spatial Services (GSS) are the built-in spatial services provided in SuperMap iServer, including: MapService, DataService, NetworkAnalystService, RealspaceService, etc.
General Layer
A general layer is a layer for loading and displaying data in a 3D scene. The locations of objects in a general layer are fixed relative to the globe, and will change with operations on the globe. For example, if the globe is panned, the objects in the layer would move with the globe.
There may be multiple general layers in a 3D scene. Styles of general layers can be set and saved in a 3D scene. When the 3D scene is opened next time, the layers will be automatically loaded with the styles saved last time.
GeoRSS
GeoRSS provides a method to contain geographical reference information in RSS (or ATOM) seed through special coding. It is an extension of RSS.
GeoRSS is a method to describe and find out the physical locations of internet contents. GeoRSS uses Geography Markup Language (GML), i.e., Extensible Markup Language (XML), to store and transfer geographical data. Supported by companies including Yahoo, Microsoft, and Google, it is practically a standard for aggregating geographical features.
GIS Service Interface
The shared boarder between human-computer interaction systems.
GIS Service Component
A service is composed of service interfaces, service components, and service providers. A service component combines and encapsulates functions of different service providers to form a coarse-grained module, such as a map component, a data component, etc.
GIS Service Provider
The direct provider of GIS services. It encapsulates and unifies different implementations of functions. It also screens the differences between different service sources. Thus different service sources correspond to different service providers.
Through encapsulating and unifying GIS functions using GIS service providers, SuperMap iServer has realized seamless integration and aggregation of multi-source heterogeneous services.
GML (Geography Markup Language)
GML is the OGC geography markup language. It adopts the simple object model of OGC, and organizes files based on the grammar and file format of XML. It can represent spatial and non-spatial attribute data of geospatial objects. GML is an application of XML in the geospatial information domain.
Heterogeneous service
A heterogeneous service is a service that an application program provides using different applications.
IDE (Integrated Development Environment)
An IDE can assist with developing programs. It usually includes a code editor, a compiler, a debugger, and a graphic user interface tool. An IDE can be used alone, or together with other programs. Currently IDEs are usually used to develop HTML application components.
Identity
The extent of the result layer of an Identity operation is the same as that of the first dataset layer. But the result layer contains the geometric objects and attribute data from the second dataset layer. The Identity operation is implemented by an Intersect operation on the first and second datasets followed by a Union operation on the Intersect result and the first dataset. The second dataset must be of the region type, while the first dataset can be of the point, line, region, or route type. If the first dataset is a point dataset, all the objects in the first dataset are reserved in the newly created dataset; if the first dataset is a line dataset, all the objects in the first dataset are retained in the newly created dataset but split at places where they intersect with the objects in the second dataset; if the first dataset is a region dataset, all the polygons in the first dataset which serves as a control boundary are retained in the result dataset but split into new polygons at places where they intersect with the objects in the second dataset.
Intersect
The Intersect operation is an operation calculating the intersection of two datasets. The result dataset reserves the overlapped portion of the two original datasets. In the two datasets, the first dataset is the dataset to be intersected, and the second dataset is the intersecting dataset. The dataset to be intersected can be of the point, line, region, route, or CAD type. But the intersecting dataset must be of the region type. The feature objects (except points) in the dataset to be intersected are split at places where they intersect with the polygons in the intersecting dataset. The spatial geometric information in the result dataset obtained from an Intersect operation is the same as that from a Clip operation. But the Clip operation does not process the attribute table, whereas the Intersect operation allows users to select the attribute fields to be retained.
Isoline
An isoline is a line connecting all neighboring points with the same values (such as elevation, temperature, precipitation, pollution, atmospheric pressure, etc.).
The distribution of isolines reflects the variation on a grid surface. The denser the isoline distribution is, the more intense the variation in the grid surface values is. For example, denser elevation isolines indicate steep slopes, and vice versa. Through isoline extraction, locations with the same elevation, temperature, or precipitation values can be found. The distribution of isolines also tells the steep and flat areas of changes.
Isoregion
An isoregion is a region formed by closing neighboring isolines. The change in isoregions can immediately reflect changes between neighboring isolines. For example, it is very intuitive and effective to use isoregions to represent elevation, temperature, precipitation, pollution, or atmospheric pressure.
As with isolines, distribution of isoregions also reflects the variation on the grid surface. The denser the isoregion distribution is, the greater the change in the grid surface values is, and vice versa. Narrow isoregions indicate greater changes at the corresponding locations, and vice versa.
JDK (Java Development Kit)
JDK is a product designed by Sun Microsystems for Java developers. JDK is the core of the entire Java. It contains a Java running environment, Java tools, and a Java foundation class library. Learning JDK is the first step in learning Java. The commonly used versions include: SE (J2SE), the standard edition; EE (J2EE), the enterprise edition; ME (J2ME), the micro edition.
JSON (JavaScript Object Notation)
JSON is a lightweight data conversion format. It is easy for people to read and compile, and also easy for machines to parse and encode. JSON is a subset of JavaScript. It adopts a text format entirely independent from the language, but does use conventions similar to those of the C language family (including C, C++, C#, Java, JavaScript, Perl, Python, etc.). These features make JSON an ideal data conversion language.
JSON is built on two types of structures: a set of "name/value" pairs and an ordered list (array) of values.
KML (Keyhole Markup Language)
KML is a markup language based on the extensible markup language grammar standard. It adopts the markup structure, and contains nested elements and attributes. KML is developed and maintained by Keyhole Inc, which is part of Google, to represent geographical features. Files compiled with KML language are KML files, with the XML file format. KML is used in software related to Google Earth (Google Earth, Google Map, etc.) for representing geographical data (including points, lines, regions, polygons, polyhedrons, models, etc.).
KVP (Keyword-Value Pair)
One method to encode WFS requests. The keyword-value pair form is used to encode a variable parameter in a request. For example: "REQUEST=GetCapabilities" is a KVP, where "REQUEST" is the keyword (the parameter name), and "GetCapabilities" is the value.
Least-cost Path
A least-cost path analysis is to find the path that passes multiple points in a given order with the least cost. "The least cost" can have various meanings. For example, it can only consider a single factor, and be defined as the least time, the lowest economic cost, the best view, the best road condition, the least bridge count, the least tollbooth count, or the most village count. It can also consider multiple factors, and be defined as the best view and the most village count, or the least time and the best road condition with the least tollbooth count.
Listener
The monitoring service monitors the corresponding report information and then sends the obtained report information to a listener. The listener then updates the information about the available service providers according to the obtained report information. If no report information is received within the time interval, the information about the available services in the corresponding GIS application or cluster service (the cluster service participating in the cluster) will be removed.
Location-Allocation
Location-allocation analysis is a process of determining one or more optimal locations for a service facility. It selects facility location(s) so that the service facility can provide service to the people it serves in the most cost-effective way. During this analysis, there is a site selection process as well as a resource allocation process. Location-allocation function can be widely applied to cases where the location(s) of a service facility in a certain region is(are) to be determined, such as determining optimal location(s) for a suburban shopping area, a fire station, a factory, an airport, a warehouse, etc.
Load Balancing
Load balancing is built on the existing network structure. It provides a cost-effective method to extend the server bandwidth, to increase the throughput, to improve the network data processing capability, and to enhance the flexibility and availability of the network. It is mainly responsible for the following tasks: providing the nearest service so that the network congestion problem can be solved and the service can be geographical-location-independent; providing users with better accessing quality; improving the service response speed; improving the utilization efficiency of the server and other resources; avoiding single point failure at critical positions on the network.
Load Balancing Algorithm
An algorithm that realizes the load balancing capability. Major load balancing algorithms include the Round Robin algorithm, the Weighted Round Robin algorithm, the Least Connections algorithm, the Weighted Least Connection algorithm, etc.
Local clustering
Local clustering in SuperMap iServer is to build a cluster of local service providers that provide the same services in order to improve the performance and efficiency of concurrent accesses
Logistics Vehicle Route
Logistics vehicle route analysis is the process of finding a cost-effective delivery route and specific paths for vehicles given M delivery centers and N delivery destinations (M and N are positive integers, and M can equal N) in a network dataset. For example, a tobacco sales company received N orders, and now needs to send delivery vehicles from M points of sale to deliver tobacco to the N order locations. Every vehicle needs to deliver tobacco to its own destinations in an optimal order. In this delivery example, delivery centers are the locations where the vehicles are dispatched, and delivery destinations are the addresses of the orders.
Network
Network is a model composed of a group of connected edges and nodes as well as their connection information. It is used to represent features such as streets and pipelines in the real world.
Network Analysis
Network analysis is the process of modeling a geographical network or utility network and optimizing the network structure and resources, by studying the network status and modeling/analyzing the flow and allocation of resources on the network. Common network analysis functions include optimal path analysis, allocation, location-allocation, etc.
Network Impedance
In real life, to travel from a starting point to a destination through a series of streets and street intersections must cost something. This cost can be measured with distance, time, money, etc. In the network model, the cost to pass a node or an edge is abstracted to impedance. In an attribute table, the field for storing impedance values is called the impedance field.
Node
A node is where edges on a network connect to each other. In real applications, a node can represent an intersection of streets, a river junction, etc. Nodes and edges correspond to two attribute tables, and their connection relationships are represented by fields in the attribute tables. In SuperMap, all the spatial information and attribute information of nodes is stored in the point sub-dataset of the network dataset.
OGC
Open Geospatial Consortium is a non-profit, international, voluntary consensus standards organization that is leading the development of standards for geospatial and location based services. The website is: http://www.opengeospatial.org
Overlay
Overlay analysis is a very important spatial analysis function in GIS. It is the process of creating a new dataset by performing a series of set operations on two datasets with the same spatial reference systems. Overlay analysis is widely applied in domains such as resource management, city development assessment, land management, agriculture, statistics, etc. Therefore, the overlay analysis class can be used to process and analyze spatial data for extracting new spatial geometric information needed by users, and also for processing the attribute information of data.
The overlay analysis class performs various overlay analysis operations on two input datasets or record sets. The operations include Clip, Erase, Union, Intersect, Identity, Symmetrical difference, and Update.
OWS (OGC Web Service)
OGC Web Service. Various web services based on the OGC standard, such as WMS, WFS, and WCS.
REST
REpresentational State Transfer (REST) is a software architecture style proposed by Dr. Roy Fielding in his Ph.D. thesis "Architectural Styles and the Design of Network-based Software Architectures" in 2000.
Reporter
A reporter informs a cluster of the information about the corresponding GIS application or available GIS services in the cluster. It sends a report to the cluster service at regular intervals (e.g., 1 second)
Request
A client's request on an operation.
Response
An operation result returned to a client by a server.
RealSpace
Realspace is a 3D geographical space and a 2D map space which is based on a geographical sphere or ellipsoid. Unlike 2D GIS which projects the real space onto a 2D plane for representation and analysis, the RealSpace technology does not need projections and directly loads data with longitudes and latitudes on a 3D globe for display. Realspace provides real 3D display of the geographical space. It has realized the integration of 2D and 3D, including: integration of 2D and 3D data, integration of 2D and 3D analyses, and integration of 2D and 3D display.
A RealSpace has two components: 3D data and 3D Scene. 3D data provide specific data, and 3D scenes provide the display of 3D data. They are analog to data and map in 2D GIS.
Rjson
A easier-to-read formatted JSON string returned by a service.
RMI (Remote Method Invocation)
RMI is a distributed object software package. It provides remote method invocation that simplifies the communication between Java applications on multiple computers. It is used to construct distributed models among Java application programs. Its essence is to invoke remote methods transparently. Just as when the program is operating on a local machine, the user does not need to be concerned about the program invocation or the specific location of the program.
SCA (Service Component Architecture)
SCA is a standard for realizing the SOA architecture design. SCA provides a programming model for building SOA-based applications and solutions. The idea is to provide business functions as a series of services, and then assemble these services into a solution to meet specific business requirements. This type of solution can create new specific services for an application. It can also reuse business logics from existing systems and applications as assembling components. SCA offers a model for assembling services as well as for creating service components, including reusing existing application functions in a SCA assembling component.
Screen Layer
A screen layer is a special layer. Different from a general layer and a tracking layer, a screen layer is not stuck on the globe in the 3D scene, but stuck on the 3D window surface instead. It is a layer static relative to the screen. In a screen layer, the sizes and locations of features relative to the realspace window are not fixed, and do not change with operations on the globe such as rotation, tilt, and zooming. With this characteristic, a screen layer is usually used to store contents that need to be displayed statically in the realspace window, such as the Logo, the operating lever, the scale, descriptive texts, etc.
A 3D scene has one and only one screen layer. Any 3D geometric objects can be added in a screen layer. The display locations and sizes of the objects can also be set. Geometric objects can also be deleted if they are not needed anymore.
Scene
A 3D scene is a scene formed by overlaying one or more layers in a certain order in Realspace and displaying the layer(s) in a window. The main body of a 3D scene is a 3D globe (with a radius of 6378137 m) simulating the Earth. This globe has a geographical reference. Points on the globe are located with longitudes and latitudes. Locations on the globe can also be easily viewed because a longitude and latitude graticule grid is provided on the globe in a 3D scene. Overlaid with remote sensing data, the globe simulates the environment above the earth, including the sky, the atmosphere, the fog, etc., to make it more real.
A 3D scene is used to load 3D layers. A 3D layer corresponds to a 3D dataset.
Service Aggregation
SuperMap iServer service aggregation is the process of integrating services of different types and sources to a SuperMap iServer system via a standard flow and then publishing them to GIS clients in a unified fashion.
Service Area
Service area analysis is the process of finding the extent in which a specified service center on a network can provide its service under a certain condition. Service area analysis can be used to analyze the service extent of a public facility such as a post office, a hospital, or a supermarket, providing assistance in selecting the optimal location of a public facility.
Service GIS
Service GIS can fully support SOA. It supports publishing all GIS functions as services according to certain standards so that the services can be employed by various clients (GIS desktop software, mobile terminals, traditional GIS components, etc.) in a cross-platform, cross-network, and cross-language fashion. It also has the service aggregation capability to integrate GIS services published on other servers.
Servlet
Servlet is a class in the Java programming language. It extends functions hosted on a server in an application with a request-response programming model. Although Servlet can respond to any types of requests, in most cases it is used to extend applications on Web servers. For this type of applications, the Java Servlet technology defines a specific HTTP-related servlet class.
The Servlet framework is composed of a javax.servlet package and a javax.servlet.http package. In the java.servlet package, the general interfaces and classes that must be implemented or extended by the Servlet class are defined. In the javax.servlet.http package, the HttpServlet class that adopts the HTTP protocol to communicate is defined.
SGM
The SGM (SuperMap Global Model) data format is a whole new format provided by SuperMap for storing 3D models. It allows a model to be quickly loaded in a scene for displaying and viewing. In addition, files are encrypted with this format to protect the data. SuperMap supports converting 3D model data (e.g., *.3ds, *.obj, *.x) that are popular nowadays to model data in *.sgm format and then loading them in a scene.
Shortest Path
A shortest path is the path with the minimum distance between two points on a network. Shortest path analysis is a special case of least-cost path analysis in which the shortest is considered optimal.
SLD
Styled Layer Descriptor is a language used to describe the Style of a layer.
SOA
SOA stands for Service Oriented Architecture. SOA can be considered as a service-oriented architecture design or model. It emphasizes on encapsulating different function units into services. The exposed interface of a service defines the service's functional and non-functional tasks and features through a contract. Services can then be integrated under internet environment, and thus are not restricted to platform environments and can be easily reused. The fundamental goal of SOA is to effectively separate system models and systems to ensure business agility.
SRS (spatial reference system)
Locations on or near the Earth surface can be represented with a spatial reference system. There are two basic types: one is based on coordinates; the other is based on geographical identifiers (e.g., zip codes, administrative districts).
SuperMap iServer Manager
SuperMap iServer Manager is a service management tool provided in SuperMap iServer. It is used to facilitate a remote, dynamic, and Web-based configuration and management model for services. Users can use SuperMap iServer Manager to easily manage GIS services.
SuperMap iServer
SuperMap iServer is a platform introduced by SuperMap for developing service GIS. SuperMap iServer series include SuperMap iServer .NET and SuperMap iServer. They are service-oriented enterprise GIS products. These products provide an enterprise system structure oriented to spatial information services. They support the SOA standard, and can be used to build enterprise network application systems and network services with powerful functionality, seamless integration of hierarchical and multi-level services, centralized service management, and highly and seamlessly extensible businesses. SuperMap iServer on servers provides network clients with GIS services with the same functions as in a profession GIS desktop product. It also offers seamless aggregation with other network services. It is a service GIS-oriented development framework that can be extended on multiple levels.
SuperMap iServer
SuperMap iServer is an enterprise service GIS product built on the Java platform. It provides powerful GIS function services, and can aggregate multi-level network services as well as custom extension services. It is a development framework suitable for the Java platform. Backstage development can be realized with Java to integrate other JakartaEE platform-based enterprise systems. SuperMap iServer can be run on Windows, Linux, and Unix.
SuperMap iServer REST API
SuperMap iServer provides REST-based application programming interfaces--SuperMap iServer REST APIs. These interfaces encapsulate most of the GIS functions including basic map functions, data editing functions, analysis functions, etc. SuperMap iServer provides these GIS functions to clients via SuperMap iServer REST APIs. Clients can obtain corresponding GIS functions by using these APIs.
SuperMap SDX+
SuperMap SDX+ is the spatial engine technology of SuperMap. It offers a universal accessing mechanism (or model) to access data stored in different engines. The engine types include database engines, file engines, and Web engines.
SuperMap SDX+ is an important component of SuperMap GIS software data models. It adopts advanced technologies on spatial data storage, spatial indexing, and data query, realizing an integrated spatial data engine technology with "integrated spatial and attribute data", "integrated vector and grid data", and "integrated spatial and business information". It thus is an ideal choice for both large and small GIS projects as well as desktop applications.
Tile Data
Tile data is the specific form of cache files of 3D data. Tile data can be uniquely identified by the corresponding index or the path of the data file. The tile data formats (for image caches and map caches) include: PNG, GIF, and JPG.
Tile Data Version
The version of certain tile data (cache file) in cached 3D data.
Tomcat
Tomcat is a free and open-source Servlet container. It can be considered as the running environment of Servlet. As the Servlet container, Tomcat receives a client's request, and transfers the request to the corresponding Servlet for processing. After the Servlet completes processing the request, the Servlet container will return the result to the client.
Traveling Salesman Problem
Traveling salesman analysis is a path analysis which does not determine the order. The salesman can decide the order in which the stops are visited. The goal is to find the traveling path with the minimum total impedance.
Traffic Rule
In a real city transportation network, specific rules are applied to many streets to help with city transportation management. For example, some streets are from-to one-way streets, some are to-from one-way streets, and some streets only allow certain types of vehicles to pass. All these network features can be represented by adding transportation network rules.
Tracking Layer
In SuperMap, every map window has a tracking layer. More specifically, every map has a tracking layer when displayed. A tracking layer is an empty and transparent layer lying on the top of all the other map layers. It is used to store some image objects and texts temporarily during a processing or analyzing process. Whenever a map is displayed, a tracking layer exists. Users cannot delete the tracking layer, or change its location. Usually a feature layer contains features of the same type. But in a tracking layer, geometric features of different types (such as point, line, and region features) and text objects can exist at the same time.
In a 3D scene, the tracking layer is a temporary layer covering the globe surface in the 3D scene for temporarily storing 3D geometric objects added in this layer. When the 3D scene is closed, the content of the tracking layer is cleared and not saved. A 3D scene can only have one 3D tracking layer. 3D geometric objects of any type can be added or deleted in a 3D tracking layer.
Transparent Clustering
In a transparent cluster, users are unaware of related servers. A cluster server assigns requests to different servers through a request allocator for processing. The request allocator servers as a request proxy. It is responsible for receiving all arriving requests and then, based on a load balancing strategy, allocating them to backend servers in a balanced and transparent fashion, .
Turn Table
Turning is the process of traveling from an edge to an immediately connected edge through a node in the middle. A turn cost is the cost to complete a turn. A turn table is used to assign turn costs. A turn table must list all possible turns at each crossing. Usually it has four fields: FromEdgeID, ToEdgeID, NodeID, and TurnCost. These fields are related to fields of edges and nodes. Every record in the table represents the edge cost to pass a crossing in some way. A turn cost is usually directional. A negative turn cost usually means that the turning is not allowed.
UGC (Universal GIS Core)
A Universal GIS core is a well-designed software structure. It effectively separates GIS functions and analysis algorithms from the information technologies they depend on, so that the two can be developed independently and do not restrict each other.
A UGC is only related to the development of core GIS technologies. The impact of changes in the IT technological environment on UGC is very limited.
A set of adaptable Universal GIS Cores need to be built to realize stable core GIS functions that are not affected by changing technological environment. On the other hand, the peripheral functions and human-machine interaction interfaces that are highly related to ever-developing technological environment can be extended based on the UGC. Once the related technological environment changes, only the peripheral function modules need to be re-implemented or adjusted. The cost of updates and changes of technology is thus greatly reduced.
Union
The Union operation is the operation that unifies two datasets. All the layer features in the two datasets are retained in the unified layer. This operation can only be performed on two region datasets. After the Union operation, the polygons are split at places where the two region datasets intersect with each other. The geometric and attribute information of the two datasets is all exported to the result dataset.
Update
The Update operation is the process of replacing the layer to be updated with the updating layer where they overlap. It is a process of erasing followed by pasting. The first and second datasets must both be region datasets. The geometric shapes and attribute information in the updating dataset are retained in the result dataset.
URI (Uniform Resource Identifier)
A URI is used to locate a resource. A URI usually consists of three components: the name mechanism of the resource to be accessed, the name of the host that stores the resource, and the resource name. It is represented by a path.
URL (Uniform Resource Locator)
URL is also called Web Page Address. A URL is the standard address of a resource on internet. URL was originally invented by Tim Berners-Lee for representing sites of World Wide Web. The World Wide Web Consortium has made it Internet standard. Uniform Resource Locator (URL) is an identifying method used to fully describe addresses of web pages and other resources on the internet. A URL consists of three components: the protocol type, the name and path of the host, and the file name.
URL is a subset of the URI naming mechanism.
VSPs (Vendor-Specific Parameters)
Optional vendor-specific parameters (VSPs) are allowed to use in a request. These parameters can enhance the response result for the request. They are especially helpful with testing non-standard functions and making them standard. Service vendors should select VSPs cautiously to avoid conflicts with standard parameters.
WCS (Web Coverage Service)
WCS is oriented to spatial image data. It takes geospatial data containing geographical locations as "coverages" and exchanges them on internet. A WCS constitutes of three types operations: GetCapabilities, GetCoverage, and DescribeCoverageType. The GetCapabilities operation returns an XML document describing the service and dataset. The GetCoverage operation in a WCS is implemented after the GetCapabilities operation has determined what kind of query can be performed and what type of data can be retrieved. It returns the geographical location value or attribute in a general coverage format. The DescribeCoverageType operation allows a client to request the full description of any coverage layer provided by a specific WCS server.
Web Application Server
Web application servers have new middleware produced under web computing environment. They provide a cross-platform running environment for creating, deploying, operating, integrating, and managing transactional web applications.
The commonly used Web application server is Tomcat.
Web Service
Web Services are Web-based enterprise applications. These applications exchange data with clients through open and XML-based standards and transport protocols.
A Web service can provide a consistent, cross-organization, and cross-developer framework which will speed the integration of application programs and application components. The Web service model has neutral language and platform. Thus developers from anywhere can create and employ a Web service. Developers can compile Web Service applications on different platforms using different languages, and then search and use these services via Web service standards.
SuperMap WebService includes four types of services: MapService, DataService, NetworkAnalystService, and SpatialAnalystService.
WFS (Web Feature Service)
WFS is one of the OGC standards. This standard is used to return feature-level GML codes, and provide transactional operations such as adding, editing, and deleting features. It is an enhancement on the Web map service.
WMS (Web Map Service)
WMS is one of the OGC standards. This standard defines three major operations for creating and displaying map images. The operations are: GetCapabilities, GetMap, and GetFeatureInfo.
Currently there are WMS version 1.1.1 and WMS version 1.3.0.
XML Schema
XML Schema is a XML-based DTD replacement. It can be used to describe the structure of an XML document. XML Schema defines the valid structural modules of an XML document. Specifically it defines the elements and attributes that can be included in a document, the order and number of the sub-elements, the data structure of the elements and attributes, as well as their default values and fixed values.
XOR
The XOR operation is an exclusive or operation on two datasets. In the operation result, for every region object, the part that overlaps with the geometric object(s) in the other dataset is removed, and the rest is retained.