poly2grid_untiled

Geometric functions poly2grid_untiled

syntax

• poly2grid_untiled(polygon_data_item, gridunit)

definition

The poly2grid_untiled function results in grid data item with a relation to the domain unit of the polygon_data_item

The resulting data item has:

• as domain unit the gridunit argument
• as values unit the domain unit of the polygon_data_item argument

description

This function is the same as poly2grid but writes singly threaded on a single mutable shadow tile that is then split into separate tiles after rendering all polygons. Compared to poly2grid, this poly2grid_untiled function will:

• take longer to calculate (as it doesn't process tiles in parallel),
• use more memory (to store the intermediate mutable shadow tile),
• but uses less CPU time (as polygons preparation is not repeated for each tile with which their bounding box intersects),
• the results are independent of the actual tiling (which could not be always true for poly2grid as the conversion to a tile-local coordinate system might cause tiling-dependent flip-cases).

applies to

• data item polygon_data_item with a wpoint, spoint, upoint, ipoint, fpoint or dpoint value type
• unit gridunit with a wpoint, spoint upoint, ipoint, fpoint, dpoint value type

conditions

1. The composition type type of the polygon_data_item needs to be polygon.
2. The domain unit of the polygon_data_item must be of value type uint32.

since version

8.7.0

example

attribute<source/district> DistrictGrid (gridunit/gridcel_10m) := 
   poly2grid_untiled(Source/District/border, gridunit/gridcel_10m);

see also

• poly2grid