public enum EncodeType extends java.lang.Enum<EncodeType>
Defines enumeration of dataset compression encode types.
For vector dataset, four encode types are supported: single-byte, double-byte, triple-byte and four-byte. The four encode types are based on the similar encoding mechanism, but the compression ratios are different, and the four encode types are lossy. Note that the point dataset and the tabular dataset can not be encoded. For raster data, DCT, a lossy encode type can be employed. ZIP, which is lossless, is applicable to vector and raster data.
Enum Constant and Description |
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BYTE
Byte, the single-byte encode type.
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DCT
DCT, the discrete cosine encode type.
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INT16
The double-byte encoding mode.
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INT24
The three-byte encoding mode.
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INT32
The four-byte encoding mode.
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LZW |
NONE
No encoding mode is employed.
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PNG
The PNG encode type.
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SGL
SGL (SuperMap Grid LZW) is a compression format defined by SuperMap.
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Modifier and Type | Method and Description |
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static EncodeType |
valueOf(java.lang.String name)
Returns the enum constant of this type with the specified name.
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static EncodeType[] |
values()
Returns an array containing the constants of this enum type, in the order they are declared.
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public static final EncodeType BYTE
A single byte is used to store a coordinate value. This encoding mode is applicable to vector data, with point and tabular datasets excluded.
public static final EncodeType DCT
DCT(Discrete Cosine Transform) is a transform encoding method widely used to compress images. This transform method provides a balance between compression ability, the quality of the reconstructed image, applicable scope and complexity of algorithm etc., and is the most widely used image compression technology recently. The principle of this method is to reduce the strong relativity that exists in the spatial domain representation through transformation, so that the signals can be expressed compactly. This method has got high compression ratio and performance, but the encoding will lack fidelity. For the image datasets usually not used to do some analysis, DCT encoding type often applies to image datasets. DCT is applicable to raster data.
public static final EncodeType INT16
2 bytes is used to store a coordinate value. This encoding mode is applicable to vector data, with point and tabular datasets excluded.
public static final EncodeType INT24
3 bytes is used to store a coordinate value. This encoding mode is applicable to vector data, with point and tabular datasets excluded.
public static final EncodeType INT32
4 bytes is used to store a coordinate value. This encoding mode is applicable to vector data, with point and tabular datasets excluded.
public static final EncodeType LZW
LZW is a widely used dictionary compression method, and from the very beginning it is used in the compression of text. The principle of LZW encoding is to use certain code to replace a section of string, the following identical string will be replaced by the same code, so this method not only can compress the repeated data, but also can compress data that does not repeat. It applies to index color images, and is a lossless encoding. (For Grid, DEM or Image dataset)
public static final EncodeType NONE
public static final EncodeType PNG
public static final EncodeType SGL
SGL is the improved LZW encoding. SGL is a more effective compression and storage manner. SGL, which is lossless, is currently employed by GRID and DEM datasetS in SuperMap. SGL is applicable to grid and image data. So far, the compression or storage used for the is the SGL encoding, and it is a lossless compression. (For Grid, DEM or Image dataset)
public static EncodeType[] values()
for (EncodeType c : EncodeType.values()) System.out.println(c);
public static EncodeType valueOf(java.lang.String name)
name
- the name of the enum constant to be returned.java.lang.IllegalArgumentException
- if this enum type has no constant with the specified namejava.lang.NullPointerException
- if the argument is null