Data are provided as GeoTIFF image files with associated TIFF world files (TFW) containing georeferencing information. GeoTIFF defines a set of publicly available TIFF tags that describe cartographic and geodetic information associated with TIFF images. GeoTIFF enables the referencing of a raster image to a known geodetic model or map projection. By using the GeoTIFF format, both metadata and image data can be encoded into the same file.
TFW files provide georeference information for the image with the same file name. Each TFW file is a text file with six numbers, described below:
Row | Description |
---|---|
1 |
the dimension of a pixel in map units in the x direction |
2 |
rotation term for row |
3 |
rotation term for column |
4 |
the dimension of a pixel in map units in the y direction |
5 |
x coordinate for upper left corner |
6 |
y coordinate for upper left corner |