Is there a QGIS plugin or other method that simplifies parcels to share a common line(border)?
I'm pretty sure I read about this some time ago. Couldn't find anything here or elsewhere.
I'd like to reduce a parcel shapefile in size to be rendered as a WMS via GeoServer.
I'm using: PostGIS 1.5 GeoServer 2.3 QGIS master(dev) Leaflet 0.6.4
QGIS uses shapefiles and shapefiles have no topology. If two areas shared a common border that border is stored in duplicate (store individual geometric objects in isolation).
GRASS GIS is a topological GIS: the adjacent geographic components in a vector map are related. The common border between two areas exists once and is shared between two areas. When you import a shapefile, it use v.clean and v.build to clean the shapefile and build the GRASS layer. For using GRASS in QGIS, see Cleaning of topology of a SHAPE file using the GRASS Toolbox.
PostGIS, since its version 2.0, has also a topology and can do the same process, see Clean Polygon. Problem, your version of PostGIS has no topology ( but you can install an initial implementation of the Topology model support (Index of /postgis-1.5.3/topology).
In the solution of Barret, GeoJSON is like a shapefile (no topology) and TopoJSON has a topology (TopoJSON). You can convert a GeoJSON file to a TopoJSON file (see Convert GeoJSON to TopoJSON) or a shapefile to a TopoJSON file (Command Line Reference)
Leaflet can use TopoJSON files (see D3 Geodata Basics – A Map Overlay can have many Faces)
GeoServer can use GeoJSON files (How do I get GeoJSON data from GeoServer into show up on my Leaflet map?) but not yet TopoJSON.
PostGIS can import GeoJSON files but not yet TopoJSON.
So, for me, the solution would be to upgrade PostGIS, import the shapefile in PostgreSQL/PostGIS, clean it and create a topology, and serve the resulting layer with GeoServer.
This might be an interesting rabbit hole to run down:
Here are some blurbs: Difference between GeoJSON and TopoJSON and How is TopoJSON different than GeoJSON
And possible real-world usability. If you can convert from TopoJSON to GeoJSON, then you could convert from GeoJSON into PostGIS.
All this being said that I have not used either TopoJSON or GeoJSON very much, and not at all in PostGIS. But, it was the first thing that came to mind when I read your question.
