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Clip a polyline with a Polygon
2 messages · Wesley Roberts, Roger Bivand
On Wed, 14 May 2014, Wesley Roberts wrote:
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?
In a complex case with multiple possible misunderstandings, you must provide a toy example; if it substantiates your claim about gIntersection, you must also state which version of rgeos you are using. Verbal hand-waving is not precise, code is more illuminating. Roger
Many thanks and kind regards, Wesley
Roger Bivand Department of Economics, Norwegian School of Economics, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 91 00 e-mail: Roger.Bivand at nhh.no