QGISers: I'm trying to realize stratified random sampling using a classification raster that I polygonized. It seems like the random points tool will create random points within each polygon, but in my case the strata are the classes, which can be scattered across a landscape -- in other words, multiple polygons make up a single strata (I'd argue this is a more valid definition of stratified random sampling). I'd like to choose, say, 10 random points falling in each group of polygons with a given shared (classification) attribute. Is there any way to realize this in QGIS? I tried pre-converting the polygonized classification file to a multi-part polygon, but the random sampling tool froze up when I used this as an input.
I dropped the polygon layer (derived from the classification raster) in: https://drive.google.com/folderview?id=0B8Kij67bij_AMmNPakJmT1p4OWc&usp=sharing The "DN" attribute is the strata I want to use (notice multiple polygons have the same DN). To be clear: I don't want 10 points per polygon, I want 10 points per "DN". Thanks! --jonathan -- Jonathan A. Greenberg, PhD Assistant Professor Global Environmental Analysis and Remote Sensing (GEARS) Laboratory Department of Geography and Geographic Information Science University of Illinois at Urbana-Champaign 607 South Mathews Avenue, MC 150 Urbana, IL 61801 Phone: 217-300-1924 http://www.geog.illinois.edu/~jgrn/ AIM: jgrn307, MSN: [email protected], Gchat: jgrn307, Skype: jgrn3007 _______________________________________________ Qgis-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-user
