Web Mapping Illustrated

Converting Raster Data to Other Formats

Raster data, like vector data, can be stored in numerous formats. Some formats come from certain software requirements or from certain satellite image sources. Some are more general while others are better suited for more complex tasks. In this section, you will see how to use the gdal_translate raster translation utility and its various parameters to help you draw the most value out of an image.

Translating an Image to Another Format

Just as ogr2ogr has several conversion options, so does gdal_translate. The syntax for the command is slightly different but similar in concept. Here is the usage:

    gdal_translate <options> <input_image> <output_image>

The options available can be listed by running the command without any parameters, as in Example 7-5.

Example 7-5. Checking the options for gdal_translate

> gdal_translate
Usage: gdal_translate [--help-general]
       [-ot {Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/
             CInt16/CInt32/CFloat32/CFloat64}] [-not_strict]
       [-of format] [-b band] [-outsize xsize[%] ysize[%]]
       [-scale [src_min src_max [dst_min dst_max]]]
       [-srcwin xoff yoff xsize ysize] [-a_srs srs_def]
       [-projwin ulx uly lrx lry] [-co "NAME=VALUE"]*
       [-gcp pixel line easting northing]*
       [-mo "META-TAG=VALUE"]* [-quiet]
       src_dataset dst_dataset

GDAL 1.2.1.0, released 2004/06/23

This first part of the output of Example 7-5 shows the various options. Each item enclosed with brackets [] is optional. Without them, the program simply converts one image ...