I am trying to create a map to show all the divisions of a country (regions, departments), but the original map (one SHP file), with a lot of detail in the boundaries, is 5-Mb sized.
I'd like to simplify the boundaries, and I'm using QGIS (Vector > Geometry Tools > Simplify Geometries). It works, I managed to reduce the size up to 3 Mb, but there are lots of gaps between two divisions.
In the original map, two different regions are separated only by the boundary. But in this second reduced map, one region is separated from its neighbour by its own boundary, then a gap, and then the neighbour's boundary.
Which is the best way to simplify the boundaries?