Can anyone clarify for me please the options in the "precision" parameter when calculating slope, aspect and curvature in GRASS GIS. What is the difference between FCELL, DCELL and CELL?
You find an explanation of FCELL, DCELL and CELL in the introduction to 2D raster maps: http://grass.osgeo.org/grass70/manuals/rasterintro.html
CELL represents integer data values,
FCELL single-points floating values and
DCELL double-precision floating point values.
Raster map data can be of type CELL, FCELL or DCELL, they are defined in "gis.h". CELL is a 32-bit signed integer, FCELL is an IEEE single-precision floating-point, and DCELL is an IEEE double-precision floating-point. 3D rasters (grid3d) is treated as DCELL (see related library).