Pro Oracle Spatial for Oracle Database 11g

APPENDIX DStoring Raster Data in Oracle

Real-world spatial features can be represented in either a vector or raster model. In a vector model, each spatial feature (a river, a road, a shop location, and so on) is represented as an object with geometric features (the shape and location) and a set of attributes. In Chapter 4, we discussed the SDO_GEOMETRY data type to store such vector spatial data. To represent the complexity of a city, for instance, you may need myriad points, lines, and polygons. A raster model, on the other hand, associates collections of pixels or cells to spatial entities by making a discrete approximation of spatial features into grid cells. Each cell takes on a single value. You can consider a raster object as a two-dimensional ...