Hi Jonathan: Interesting puzzle. You can get what you wish if you use GRASS (r.mapcalc and r.null). With QGIS I just got zero or null, but band by band:
ZERO : (band1@1<=145)*band1@1 NULL : ( ((band1@1<=145)*band1@1) / ((band1@1<=145)*band1@1) ) * band1@1 Explanation: 1. ZERO: When condition in parenthesis is true, it goes 1, if doesn't, 0. After that, multiply by the same band, so result is 0 in cells that original value was major than 145, and it's the same value as original in other cells. 2. NULL: We have same prior value divided by himself. In cells where we got 0, now will get NULL, and the original value in other cells. I used 145 according your example. Good luck Carlos 2014-02-21 8:37 GMT-05:00 Jonathan Moules < jonathanmou...@warwickshire.gov.uk>: > Hi List, > I have a three band raster. I want to do the following with: > > If (Band1 > 150 AND Band2 > 150 AND Band3 > 150){ >> Band1 = 255 >> Band1 = 255 >> Band1 = 255 >> } > > > Basically set all band values to 255 when all band values are > than a > value of 150. All other band values should remain unchanged. > > How do I do this? I've got as far as the below for the : > >> ( "CR0569TEI_00008_modified@1" > 145 AND "CR0569TEI_00008_modified@2" > >> 145 AND "CR0569TEI_00008_modified@3" > 145 ) > > > But am unsure what's next. The tutorials I've found online assume I only > want 1 or 0 as my results. > > Help welcome. :-) > Thanks, > Jonathan > > This transmission is intended for the named addressee(s) only and may > contain sensitive or protectively marked material up to RESTRICTED and > should be handled accordingly. Unless you are the named addressee (or > authorised to receive it for the addressee) you may not copy or use it, or > disclose it to anyone else. If you have received this transmission in error > please notify the sender immediately. All email traffic sent to or from us, > including without limitation all GCSX traffic, may be subject to recording > and/or monitoring in accordance with relevant legislation. > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-user >
_______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user