Although the raster type is vastly different in makeup from the geometry type, in PostGIS you’ll find the
two have a very fluid relationship. In this chapter we'll mostly focus on raster functions that take
as input a single raster or a geometry and output a scalar value, another raster or another geometry. In chapter 9 and 12 we'll explore interaction between raster and geometry in more detail when we explore the spatial relationships supported between the two and how leveraging these relationships makes it easy to do statistics on bounded geographic regions, clip rasters with geometries, and create hybrid rasters by overlaying several rasters.
Stay tuned for our next book pgRouting: A Practical Guide published by Locate Press due out in hard-copy 4th quarter 2017. Content is now feature complete and can purchase e-Book draft and get final when goes to print.
© Leo Hsu and Regina Obe 2014