<div dir="ltr">Hi Carlos,<div> Thanks for your thoughts. One observation - it appears that you are only checking a single band at a time.</div><div>However I only want the values to be changed if ALL bands have a value of >145. If only one or even two of the values are >145 then nothing should be changed, it's only when all three are that I want it to be triggered.<br>
</div><div><br></div><div>That makes the problem even more tricky. :-)</div><div>Kind Regards,</div><div>Jonathan</div><div><div class="gmail_extra"><div><br></div>
<br><br><div class="gmail_quote">On 21 February 2014 21:40, Carlos Cerdán <span dir="ltr"><<a href="mailto:sig.upagu@gmail.com" target="_blank">sig.upagu@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Hi Jonathan:<br><br>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:<br><br>ZERO : (band1@1<=145)*band1@1<br><br>
NULL : ( ((band1@1<=145)*band1@1) / ((band1@1<=145)*band1@1) ) * band1@1 <br><br>Explanation:<br><br>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.<br>
<br>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.<br><br>I used 145 according your example. <br><br>Good luck<br><br>Carlos<br><br>
</div><div class="gmail_extra"><br><br><div class="gmail_quote">2014-02-21 8:37 GMT-05:00 Jonathan Moules <span dir="ltr"><<a href="mailto:jonathanmoules@warwickshire.gov.uk" target="_blank">jonathanmoules@warwickshire.gov.uk</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr">Hi List,
<div>I have a three band raster. I want to do the following with:</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
If (Band1 > 150 AND Band2 > 150 AND Band3 > 150){<br> Band1 = 255<br> Band1 = 255<br> Band1 = 255<br>}</blockquote><div><br></div><div>Basically set all band values to 255 when all band values are > than a value of 150. All other band values should remain unchanged.</div>
<div><br></div><div>How do I do this? I've got as far as the below for the :</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
( "CR0569TEI_00008_modified@1" > 145 AND "CR0569TEI_00008_modified@2" > 145 AND "CR0569TEI_00008_modified@3" > 145 ) </blockquote><div><br></div><div>But am unsure what's next. The tutorials I've found online assume I only want 1 or 0 as my results.</div>
<div><br></div><div>Help welcome. :-)</div><div>Thanks,</div><div>Jonathan</div></div>
<br>
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