[Qgis-user] aggregate map of maximum value

[Nicolas Cadieux]

Hi, 
I am not sure you can use max value in QGIS raster calculator. (Please correct me if I am wrong). 
I think you can do it with gdal calc.py.  and most likely in Grass or Saga using the processing plugin. 
http://gis.stackexchange.com/questions/107257/combine-overlapping-rasters-in-gdal-calc-py-taking-the-maximum-value-from-each 
If you want more flexibility but don't mind the lost of speed, you could convert the raster in a vector format and use the field calculator to do it. This work's OK up to a few million points or pixels. After that, it's very slow.  You can speed things up by using R for the statistics. 
I think there is a raster to point module in the QGIS processing plugin or just look at this:  
http://fr.slideshare.net/shencoop/qgis-raster-to-point 
Then you could do the reverse operation on the results. 
Nicolas Cadieux M.Sc. 
Les Entreprises Archéotec inc.  
8548, rue Saint-Denis Montréal H2P 2H2 
Téléphone: 514.381.5112  Fax: 514.381.4995 
www.archeotec.ca 
On Jul 7, 2015 8:06 AM, "Giacomo Fontanelli-2 [via OSGeo.org]	" <ml-node+s1560n5214622h43 at n6.nabble.com> wrote: 

	dear community I have a stack (bsq) of 5 images. I would like to make an aggregate map of the maximum of each pixel of the bands. I Googled and I found contrasting opinions on how to do it. Can you help me? Thank you 
_______________________________________________
Qgis-user mailing list
[hidden email] 
http://lists.osgeo.org/mailman/listinfo/qgis-user 

	
	
	
	
	
	
	
		If you reply to this email, your message will be added to the discussion below: 
		http://osgeo-org.1560.x6.nabble.com/aggregate-map-of-maximum-value-tp5214622.html 
	
	
		To start a new topic under Quantum GIS - User, email ml-node+s1560n4125267h38@n6.nabble.com 
		To unsubscribe from Quantum GIS - User, click here . 
		NAML 
	



--
View this message in context: http://osgeo-org.1560.x6.nabble.com/aggregate-map-of-maximum-value-tp5214622p5214684.html
Sent from the Quantum GIS - User mailing list archive at Nabble.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20150707/d05e1ee3/attachment.html>