[geos-devel] Removing multiple vertices

Paul Meems bontepaarden at gmail.com
Thu Apr 11 11:57:30 PDT 2019


Hello,

Currently, I'm working on improving the Shapefile editor of
MapWinGIS/MapWindow5.
Under the hood, it is using a lot of GEOS functions.

When opening a shapefile we can draw a temporary polygon and use it to
erase a part of the shapefile. We use GEOS::Difference to 'eat' the drawn
polygon from the shapefile.
This works fine.

We now want a similar option. But this time not 'stamp' the drawn polygon
on the shapefile but remove all vertices of the shapefile that are inside
(under) the drawn polygon.

Does GEOS have a method for that or should I just loop through all vertices
of the shape and check if it is inside the drawn polygon and remove it when
it does?

Thanks for any advice,

Paul

*Paul Meems *
Release manager, configuration manager
and forum moderator of MapWindow GIS.
www.mapwindow.org

Owner of MapWindow.nl - Support for
Dutch speaking users.
www.mapwindow.nl


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