IsoPoly2

Function IsoPoly2(filename: string; nodenum: integer; Doughnut: boolean; Xlong1,Ylat1,Xlong2,Ylat2: double): integer;

IsoPoly2 calculates isocost polygons, which shows how far it is possible to go within a specified amount of cost from one or more nodes.

The result is saved to filename, which should include path and filename, but exclude extension.

The output format is determined by property GISformat.

Nodenum specifies the number of nodes entered into the standard nodelist.

It is possible to define, that doughnut polygons should be generated, e.g 0-5 minutes, 5-10 minutes etc. or standard polygons e.g. 0-5 minutes, 0-10 minutes etc.

Use procedure StepsClear and StepsAdd to add a list of the actual isochrones generated.

The best way to understand these parameters is to try rwnetdemo.exe, which makes it possible to adjust the parameters easily and see the result immediately.

It is possible to define a bounding box for the calculation. If it doesn't cover at least all nodes in the nodelist, it is extended to do so. Specifying all 0's means it just covers the whole network. See also IsoPoly2Fast.

See also property AddNodes and separate discussion.

Latitude/longitude coordinates are not really supported by this function, but only in rare situations will it actually affect the generated polygons.

Possible error codes: -10 -30 -40 -41 -43

Versions: Standard Pro

ActiveX / VCL / CLX component: RWcalc