Chapter 7. Raster functions

This chapter covers:

Constructor functions

Output functions

Raster band and pixel accessors and setters

Georeferencing functions

Reclassing functions

Polygonizing functions

The raster type is different in makeup from the geometry type covered in chapter 6. Geometries model an object as a set of linear equations, whereas rasters model an object as a tapestry of cells. In PostGIS, you’ll find the two types working together, leveraging each other’s strengths. For example, you can output a geometry in a raster file format such as PNG. You can also clip raster images with vector boundaries. We’ll touch on raster processing in this chapter, but we’ll leave the more thorough treatment for chapter 12, where we’ll demonstrate ...

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