Raster files represent a terrain by its image at a certain altitude and contain metadata that allows setting the image in the right place above an electronic map. Working with raster data is a little different from working with vectorial data. First, we must define a table with a field of raster type instead of the geometric type that we have used in previous chapters.
We will need to use the GDAL
raster2pgsql command; this tool will generate the appropriate SQL sentences to create the spatial table and insert data into it. We will work with the
GBOverview.tif file that we used in Chapter 5, Displaying GIS Data Graphically.
Before we start, we need to get a little information on this file; in this case, we must know what ...