L_INT LFile::ReadGeoKey(uTag, puType, puCount, pData, pLoadOptions)
Gets the specified GeoKey data from a TIFF file. This function is provided to support GeoKeys that you define.
GeoKey ID that you set by calling LFile::SetGeoKey function. Values of the GeoKey ID range between 0 and 65535. Possible ranges are:
Range | Meaning |
---|---|
0..1023 | Do not use; reserved for future use. |
1024..2047 | GeoTIFF configuration keys. |
2048..3071 | Geographic/Geocentric CS Parameter Keys. |
3072..4095 | Projected CS Parameter Keys. |
4096..5119 | Vertical CS Parameter keys. |
5120..32767 | Reserved. |
32768..65535 | Private use use to store your own data. |
Pointer to a variable to be updated with the GeoKey type. This indicates whether the data pointed to by pData is SHORT, DOUBLE or ASCII. Possible values are:
Value | Meaning |
---|---|
TAG_ASCII | [2] The data pointed to by pData is an array of ASCII bytes. |
TAG_SHORT | [3] The data pointed to by pData is an array of SHORT values (2 bytes each). |
TAG_DOUBLE | [12] The data pointed to by pData is an array of floating points in DOUBLE format (8 bytes each). |
TAG_IFD | [13] 32-bit IFD offset. |
TAG_LONG8 | [16] Unsigned 64-bit integer (valid only for BigTIFF formats). |
TAG_SLONG8 | [17] Signed 64-bit integer (valid only for BigTIFF formats). |
TAG_IFD8 | [18] 64-bit IFD offset (valid only for BigTIFF formats). |
Pointer to the variable to be updated with the number of items required for the pData buffer. Note that this is not the required number of bytes. The required number of bytes will be (*puCount) * number of bytes per value (1 for ASCII, 2 for SHORT, 8 for DOUBLE).
If pData passed as NOT NULL, this variable will be updated with the count of data items.
Pointer to the buffer to be updated with the data. You can pass NULL if you want to use this function's return value to determine the required buffer size.
Pointer to optional extended load options. Pass NULL to use the default load options.
Value | Meaning |
---|---|
SUCCESS | The function was successful. |
< 1 | An error occurred. Refer to Return Codes. |
Obtains the GeoKey data from a particular file.
It is often convenient to call this function twice, as follows:
The most efficient way of reading the GeoKeys in a file is to enumerate them with LFile::EnumGeoKeys and then read each GeoKey with LFile::ReadGeoKey.
For more information about GeoKeys, refer to Implementing GeoKeys (GeoTIFF tags).
Win32, x64.
For an example, refer to LFile::WriteGeoKey function.
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