[Qgis-user] making mistakes with raster calculator

[Nicolas Cadieux]

Hi, 
The result of you operation will give you a raster with 0 (does not correspond ) and 1 (does correspond).  Then you need to multiply result that by 5. You can do it in one shot such as (raster < 2)*5.  If you do (raster <2)*raster, the results (1) will be multiplied by the original values of the raster. All other value will be multiplied by 0. 
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 
Le 2015-04-08 18:30, "Giacomo Fontanelli-2 [via OSGeo.org]	" <ml-node+s1560n5200510h71 at n6.nabble.com> a écrit : 

	Dear forum I use QGIS 2.8.1. I have a raster map, Float32, pixel values range from -0.7 to 1. I Would like to make a map with pixel having only two values: pixels with values <= 0 should be 0 pixels with values > 0 should be 5. the sintax ( "3_NDFI@1" <= 0 ) =0 AND  ( "3_NDFI@1" > 0 ) =5 doesn't work because it produces a map with only 0 values. In order to reach my goal I must do ( "3_NDFI@1" <= 0 ) =0 AND  ( "3_NDFI@1" > 0 ) =1 then multiply result by 5. What's the problem?  Is it possible to fulfil the purpose with only one raster operation? Thank you very much 

_______________________________________________
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/making-mistakes-with-raster-calculator-tp5200510.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/making-mistakes-with-raster-calculator-tp5200510p5200514.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/20150408/02f66195/attachment.html>