5
votes
1answer
198 views

How to extract vectors from map using QGIS?

I am trying to extract building footprints from a raster map (as shown in the example below). Please note that the maps are out of copyright, have been scanned and georectified by a library and have ...
5
votes
1answer
266 views

Simplifying polygons made from binary rasters

I'm using MaxEnt to produce a species presence / absence raster layer. It works fine but I have to choose a cut off point for what constitutes presence or absence. As a result I end up with a lot of ...
2
votes
1answer
2k views

Converting Raster Data to Polygon data

I am trying to convert a raster data to polygon data. Previously I was using the shapefile.py to create point data on individual lat/lon on the raster. But that will create a Huge data and querying it ...
4
votes
2answers
584 views

Extract all pixels of given RGB value and render as MultiPolygons

Given a geotiff image with a colortable in it, what is the easiest way to extract each color as its own "layer or shapefile or multipolygon object"? Specifically, I am looking for a programmatic ...