Question

Polygons not covered with lines

N
Hi,

 

 

i have two shapes, polygon and lines. How to find polygons that is not completely covered with lines? Tnx

5 replies

takashi
Rank
Userlevel 2
Badge +17
Hi,

 

 

If you need to find polygons which never overlap any line, apply the LineOnAreaOverlayer, and look at overlap count attribute (named "_overlaps" by default) of the output Areas.

 

 

Takashi
N
no, for example, i have one polygon and five lines that form the polygon. For example, one of these five lines are missing and i need that polygon in result.
takashi
Rank
Userlevel 2
Badge +17
OK. How about this approach?

 

Send the lines to the LineJoiner --> GeometryCoercer (Geometry Type: fme_polygon).

 

If the lines forms a polygon, output will be a polygon. If not, output is still a line.

 

Then, select output lines (GeometryFilter), and compare them with the polygons to select required polygons (SpatialFilter etc.).
takashi
Rank
Userlevel 2
Badge +17
Alternatively, the AreaBuilder could be used instead of the LineJoiner and GeometryCoercer.
G
Badge +3
GeometryCoercer on the polygon and than SpatialRelator between inputlines and the coerced lines from the polygon.

 

If topology is the same you can use "Equal".

 

If it is not, "INTERSECT". Calclate cardinality and test for relationships{}.card.line>0

 

Tis will eliminate the bare line.

 

 

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