4

I tried to do a raster Weighted Overlay Suitability Analysis to find the best location for home lands using QGIS. Used layers are:

  1. School location (point)
  2. Crime locations (point)
  3. Road (line)
  4. Water lines (line)
  5. Towns (point)

My procedure is to first convert to distance each layer and apply the Weighted Sum Overlay method. I used Raster > Rasterize to convert but the result was a black square and it can't apply styles. If anybody knows the correct steps, please help me. Next if it is ok, what is the tool for weighted sum in ArcGIS?

  • 1
    So is the problem you're having with overlay analysis (as the title suggests) or is it with vector-to-raster conversion, as the text suggests? – WhiteboxDev Sep 30 '14 at 12:06
  • Ahh I missed your comment @WhiteboxDev, the question was a bit ambiguous. I will delete my post if the problem does not concern raster styles. – Joseph Sep 30 '14 at 12:11
  • @WhiteboxDev many thanks buddy! Will wait for the OP to respond and will let you answer if the problem lies with the Overlay analysis or with the vector-to-raster conversion as I am not very familiar with either of them. – Joseph Sep 30 '14 at 12:49
3

Have you tried changing the Render type? I normally use Singleband pseudocolor:

Raster style

You can then apply a certain colour to various value of the raster:

Raster color

EDIT

The tool in QGIS that is the (near) equivalent to ArcGIS's weighted overlay tool is the 'Ordered Weighted Averaging' tool. It can be found within the SAGA QGIS plugin, which may, depending on your set-up require additional installation.

  • No worries, you did the heavy lifting here ;) – WhiteboxDev Sep 30 '14 at 13:08
  • Thanks, It is ok, I did the classification as you explaining for the Road, Waterlines. 'Thank you very much for all your help and useful information. it was very useful to me in this problem. Next my problem is converting Point layers to raster. When I convert using Raster> Rasterize it display as one color box I check metadata Min Values=0 and Max value=1 But I can't classify it same as line layers (Road/Water lines). Next problem is how to apply weighted overlay tool. and what is it in QGIS? Nethsiri Jayaweera – Nethsiri Jayaweera Oct 2 '14 at 7:59
  • If you have another problem, it would be best to ask it as a new question. – Joseph Oct 2 '14 at 9:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.