Dear r-sig-geo,

I have been looking for a tool / method to clip a polyline using a polygon
and cant seem to find a suitable solution. My task is as follows.

I have a property boundary which is a polyline. I have a deforestation
layer which is a polygon. In my property data set I have 23 boundaries. I
need to calculated the ratio of threatened perimeter to actual perimeter.
To do this I select each boundary and then clip the boundary with the
deforestation layer. The boundaries that remain (are spatially coincident
with the deforestation layer) then remain. I calculate the length of these
and calculate my ratio. This task is very straight forward and can be easy
accomplished using QGIS, however, I have shared boundaries and thus need to
process each boundary separately. gIntersection does not return what I need.

Can anyone help with a potential solution?

Many thanks and kind regards,
Wesley

-- 
Dr Wesley Roberts
jwesroberts@gmail.com
Cell: +27(0)83 5355 646
skype: roberts-w

I hear...I forget
I see...and I remember
I do...and I understand
Ancient Chinese Proverb

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