Raw
binary format
The raw binary format is a simple format that was developed in the early days of computing as a means to store and exchange raster data. It supports only one raster per file, which can have multiple bands that have a common data type. Only a few data types are supported. A header file is required to open the file. A third file with coordinate system information is optional.
| General |
Simple file-based format for a single raster with 1 or more bands having a single data type. |
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| Read |
The driver reads all common forms of raw binary files, with the exception of data in 1 and 4 bit lengths. 8 Bit data is interpreted as dspUInt8, 16 bit data as dspInt16, and 32 bit data as dspInt32. Other data types are not supported by this format. (You can use the gridmath module to convert the data to other types, if necessary.) A header file with the same name as the data file but with a .HDR extension is required. Starting skip bytes, row fill bytes, and band gap bytes are all supported. Conversion between little and big endian byte ordering is performed automatically. The ULXMAP and ULYMAP tie points are considered to represent the center of the upper-left pixel. |
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| Write |
The driver can write a new file, or modify an existing file. When modifying an existing file, the structure of the file (e.g. row fill bytes, band gap bytes, layout, byte ordering) is maintained. New files will always use big endian byte ordering, BIL layout, and no header bytes, row filler, or band gap bytes. A header file is automatically created, if required, as well as a coordinate system information file. |
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| Attributes | This format does not include any attributes. | ||||||||||||||||||||||||||||||||||||||||||||||||
| Coordinate system |
If, when reading, a file with the same name as the data file but with a .PRJ extension is found, this file is parsed for coordinate system information. This information needs to be in the ESRI PRJ format. If no such file is found, or if the parsing is unsuccessful, a local coordinate system is assigned. |
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| Documentation | No additional documentation identified. | ||||||||||||||||||||||||||||||||||||||||||||||||
| Data sources | This format is a least-common-denominator for raster data, and most commercial packages support it in one form or another. Many data sources on the internet will also offer data in this format. | ||||||||||||||||||||||||||||||||||||||||||||||||
| Developer information |
Typically, the data files are in a flat binary layout, with no header bytes, row filler bytes, or band gap bytes, but all other layouts are supported. The accompanying header file can have the following keywords (in no particular order):
Keywords that do not have a default value must be present in the header file. |