[pgrouting-users] Setting the tolerance argument in assign_vertex_id

[Dan Putler]

Hi,

I'm curious how to determine the value of the second argument in the function assign_vertex_id(). Most of the examples I can find look like:

assign_vertex_id('<edge table>', 0.001, 'the_geom', 'gid')

Most of the examples are based on edge tables that have SRIDs that correspond to either WGS84 geographic or some sort of US State Plane feet. I'm using data that is using a UTM coordinate SRID, so the map units are in meters. My question is whether the map units should influence the choice of the second argument to the function (which I assume is a tolerance between edges), or should I just keep with the value 0.001? Implicitly, I'm asking if the parameter is in the map units of the SRID.

Dan