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PostGIS in Action by Leo Hsu, Regina Obe

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Chapter 5. Relationships between geometries

 

This chapter covers
  • Intersections and differences
  • Intersect relationship types
  • Equality
  • Nearest neighbor
  • Arbitrary relationships
  • Dimensionally Extended 9 Intersection Model (DE9IM)

 

As the old saying goes, “No man is an island”; the same holds true for geometries. In the previous chapter we concentrated on describing geometries in isolation. We described common properties for geometries and various functions to measure, morph, or transform single geometries. From this chapter forward, we’ll no longer entertain ourselves with one geometry at a time. The richness and the power of spatial queries really come to light when we start working with more than a single geometry. If we liken geometries ...

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