Manifold Community Site: Topology Overlay Identity with Overlapping Areas

RE: Topology Overlay Identity with Overlapping Areas

BCowper — Thu, 29 Sep 2011 17:07:18 GMT

I've been scratching my head on this one: I have a Line Drawing representing a pipeline and a Drawing that contains Areas some of which overlap, the Areas represent various species. I want to find a way of replicating the Topology Overlay Identity function so that I end up with Line features that indicate the extent of each species along the pipeline.

My problem with the Identity command is where the Areas overlap I will only get data transferred from one of the Areas. Ideally I would want a Line created for each species extent, creating duplicate Lines where the species Areas overlap.

RE: Topology Overlay Identity with Overlapping Areas

tjhb — Thu, 29 Sep 2011 21:36:15 GMT

Would a query do Brian?

OPTIONS COORDSYS("Lines" AS COMPONENT);

SELECT

ClipIntersect([L].[Geom (I)], [A].[Geom (I)]) AS [Section],

[A].[Species]

FROM

[Lines] AS [L]

INNER JOIN

[Areas] AS [A]

ON Touches([L].[Geom (I)], [A].[Geom (I)])

AND ClipIntersect([L].[Geom (I)], [A].[Geom (I)]) IS NOT NULL

;

RE: Topology Overlay Identity with Overlapping Areas

BCowper — Thu, 29 Sep 2011 22:14:49 GMT

You're a life saver yet again Tim, thanks I must be at least up to a keg of beer owing!

I have a species ranking column too and can plug that in to the query and use an Order By at the end using the ranking column to control the display order of the lines. Fantastic.