Skip to content

Try using addition for buffer of multipolygons #524

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
eyal0 wants to merge 1 commit into from
Closed

Try using addition for buffer of multipolygons #524

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
53 changes: 29 additions & 24 deletions bg_helpers.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -14,12 +14,14 @@ namespace bg_helpers {
// The below implementations of buffer are similar to bg::buffer but
// always convert to floating-point before doing work, if needed, and
// convert back afterward, if needed. Also, they work if expand_by is
// 0, unlike bg::buffer.
// 0, unlike bg::buffer. It seems to be faster to buffer individual
// polygons and then add them together rather than to do them all at
// once, even though the results ought to be the same. How strange!
const int points_per_circle = 32;

multi_polygon_type_fp buffer(multi_polygon_type_fp const & geometry_in, coordinate_type_fp expand_by) {
if (expand_by == 0 || geometry_in.size() == 0) {
return geometry_in;
multi_polygon_type_fp buffer(polygon_type_fp const & geometry_in, coordinate_type_fp expand_by) {
if (expand_by == 0) {
return multi_polygon_type_fp{geometry_in};
}
#ifdef GEOS_VERSION
geos::io::WKTReader reader;
Expand Down Expand Up @@ -50,9 +52,9 @@ multi_polygon_type_fp buffer(multi_polygon_type_fp const & geometry_in, coordina
#endif
}

multi_polygon_type_fp buffer_miter(multi_polygon_type_fp const & geometry_in, coordinate_type_fp expand_by) {
multi_polygon_type_fp buffer_miter(polygon_type_fp const & geometry_in, coordinate_type_fp expand_by) {
if (expand_by == 0) {
return geometry_in;
return multi_polygon_type_fp{geometry_in};
} else {
multi_polygon_type_fp geometry_out;
bg::buffer(geometry_in, geometry_out,
Expand All @@ -65,20 +67,29 @@ multi_polygon_type_fp buffer_miter(multi_polygon_type_fp const & geometry_in, co
}
}

template<typename CoordinateType>
multi_polygon_type_fp buffer(polygon_type_fp const & geometry_in, CoordinateType expand_by) {
return buffer(multi_polygon_type_fp{geometry_in}, expand_by);
multi_polygon_type_fp buffer(multi_polygon_type_fp const & geometry_in, coordinate_type_fp expand_by) {
if (expand_by == 0 || geometry_in.size() == 0) {
return geometry_in;
}
multi_polygon_type_fp geometry_out;
for (const auto& poly : geometry_in) {
geometry_out = geometry_out + buffer(poly, expand_by);
}
return geometry_out;
}

template multi_polygon_type_fp buffer(polygon_type_fp const&, double);

template<typename CoordinateType>
multi_polygon_type_fp buffer_miter(polygon_type_fp const & geometry_in, CoordinateType expand_by) {
return buffer_miter(multi_polygon_type_fp{geometry_in}, expand_by);
multi_polygon_type_fp buffer_miter(multi_polygon_type_fp const & geometry_in, coordinate_type_fp expand_by) {
if (expand_by == 0) {
return geometry_in;
}
multi_polygon_type_fp geometry_out;
for (const auto& poly : geometry_in) {
geometry_out = geometry_out + buffer_miter(poly, expand_by);
}
return geometry_out;
}

template<typename CoordinateType>
multi_polygon_type_fp buffer(linestring_type_fp const & geometry_in, CoordinateType expand_by) {
multi_polygon_type_fp buffer(linestring_type_fp const & geometry_in, coordinate_type_fp expand_by) {
if (expand_by == 0) {
return {};
}
Expand Down Expand Up @@ -111,8 +122,7 @@ multi_polygon_type_fp buffer(linestring_type_fp const & geometry_in, CoordinateT
#endif
}

template<typename CoordinateType>
multi_polygon_type_fp buffer(multi_linestring_type_fp const & geometry_in, CoordinateType expand_by) {
multi_polygon_type_fp buffer(multi_linestring_type_fp const & geometry_in, coordinate_type_fp expand_by) {
if (expand_by == 0 || geometry_in.size() == 0) {
return {};
}
Expand Down Expand Up @@ -148,13 +158,8 @@ multi_polygon_type_fp buffer(multi_linestring_type_fp const & geometry_in, Coord
#endif
}

template multi_polygon_type_fp buffer(const multi_linestring_type_fp&, double expand_by);

template<typename CoordinateType>
multi_polygon_type_fp buffer_miter(ring_type_fp const & geometry_in, CoordinateType expand_by) {
multi_polygon_type_fp buffer_miter(ring_type_fp const & geometry_in, coordinate_type_fp expand_by) {
return buffer_miter(polygon_type_fp{geometry_in}, expand_by);
}

template multi_polygon_type_fp buffer_miter(ring_type_fp const&, double);

} // namespace bg_helpers
12 changes: 4 additions & 8 deletions bg_helpers.hpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,17 +20,13 @@ multi_polygon_type_fp buffer(multi_polygon_type_fp const & geometry_in, coordina

multi_polygon_type_fp buffer_miter(multi_polygon_type_fp const & geometry_in, coordinate_type_fp expand_by);

template<typename CoordinateType>
multi_polygon_type_fp buffer(polygon_type_fp const & geometry_in, CoordinateType expand_by);
multi_polygon_type_fp buffer(polygon_type_fp const & geometry_in, coordinate_type_fp expand_by);

template<typename CoordinateType>
multi_polygon_type_fp buffer(multi_linestring_type_fp const & geometry_in, CoordinateType expand_by);
multi_polygon_type_fp buffer(multi_linestring_type_fp const & geometry_in, coordinate_type_fp expand_by);

template<typename CoordinateType>
multi_polygon_type_fp buffer(ring_type_fp const & geometry_in, CoordinateType expand_by);
multi_polygon_type_fp buffer(ring_type_fp const & geometry_in, coordinate_type_fp expand_by);

template<typename CoordinateType>
multi_polygon_type_fp buffer_miter(ring_type_fp const & geometry_in, CoordinateType expand_by);
multi_polygon_type_fp buffer_miter(ring_type_fp const & geometry_in, coordinate_type_fp expand_by);

} // namespace bg_helpers

Expand Down