Floating-point raster data must be converted into integer raster data before it can be used for weighted superposition.

Raster data is a data form that divides space into regular grids. Each grid is called a unit, and each unit is given corresponding attribute values to represent entities.

There are three ways to obtain raster data: grating method, conversion method, scanning digitization and classified image input. Its advantages include simpler data structure, more powerful format, and rapid superposition of complex data sets.