qgisqgis-plugins
I found the following link to a post saying that a count lines in polygons had been added to ftools for QGIS:
http://hub.qgis.org/issues/4712
However I can't find how to access this feature nor any online discussion of how to do this – can anyone help?
Alternatively, are there any other tools that will allow this?
I have a hexagonal grid and want to count the number of animal track paths that go through each cell for a migratory distribution map.
Thanks
In this case, it looks like you need to help the dissolve tool along by fixing the topology first. Here's how you can do this in GRASS.
When you load the shapefile, this is how GRASS sees it:
Each cross marks an area. You can see that there are some crosses on the boundary lines: These are the sliver polygons caused by the slight offset between the boundary lines.
Remove the sliver polygons formed by the gaps between the real polygons:
v.clean input=sample output=tempA --o tool=rmarea thresh=0.001
Snap the boundary lines:
v.clean input=tempA output=tempB --o tool=snap thresh=0.001
Break the boundary lines at the new intersections:
v.clean input=tempB output=tempA --o tool=break thresh=0.001
Remove the now duplicate boundary lines:
v.clean input=tempA output=tempB --o tool=rmdupl thresh=0.001
Dissolve the polygons
v.dissolve input=tempB output=cleaned --o column=ID
Et voilà:
Best Answer
I couldn't find the field count in the fTools anymore (QGIS 2.0). But I managed to get the number of lines within a polygon using the plugin MMQGIS. Assuming you have a line layer test.shp and a polygonlayer buffers.shp you have to do the following:
The output file example.shp contains the attribute count, which gives you the number of lines within each polygon.