Hello, Yes, I did remove the spaces and fixed it as mentioned in the various emails. It is working now. Newbie mistake I guess.
Thank you all for the wonderful support. I appreciate it! Wanda On Mon, Feb 15, 2021 at 3:53 PM Nicolas Cadieux <njacadieux.git...@gmail.com> wrote: > Thayer’s instructions look good. > > Start by building query one step at a time. You can separate the parts > using the pipe sign ||. Then, change the || for the operators OR. That > would help you trouble shoot the operation. > > I think he is right. The problem is likely the space between <=. > > Nicolas Cadieux > https://gitlab.com/njacadieux > > Le 13 févr. 2021 à 10:57, Thayer Young <thaye...@yahoo.com> a écrit : > > > Hi Wanda, > > Please try removing the spaces between the operators, the tool should not > run with those spaces: > they should be: <= and >= not < = and > = > > Also make sure that the name of the raster layer is EXACTLY the same as > what you have in your Layers panel (what the ESRI work calls Table of > Contents). The double quotes around the name are there just in case you > have a space in the name of the raster Layer. You can safely remove them if > there are no spaces. The parenthesis are also not necessary, because of the > order of operations (the same as in basic algebra). The <= and >= will > calculate before the OR, so there is no need for parenthesis. You would > only need parenthesis if the expression were more complicated. > The following should work equally well: > > Aspect@1<=90 OR Aspect@1>=270 > Aspect@1 <= 90 OR Aspect@1 >= 270 > "Aspect@1" <= 90 OR "Aspect@1" >= 270 > ("Aspect@1" <= 90) OR ("Aspect@1" >= 270) > > But if your layer is named "Aspect" but you enter "aspect", the raster > calculator will say the expression is valid but then show a red banner > error after it is run. > This is because the expression looks fine to the raster calculator tool, > but it does not check for the existence of the layer until you press OK. In > this case it can not find a layer "aspect" because the layer is named > "Aspect". > > I have tried reproducing your problem using the OSGeo4W Network Installer > QGIS 10.10 without GRASS, but I am not able to. If the recommendations > above are not helpful, you may need to give more specifics about the errors > you are seeing and which installation you are using. I hope this helps :-) > > -Thayer > > P.S. I did have a problem with the extent not being set correctly when I > had more than one DEM. Everything ran without errors, but the result was > empty, except for a thin band where the two DEMs overlapped. You may need > to be careful to set this to the correct extent, so click on your Aspect > layer and then Selected Layer Extent. > > > > ====================================================== > Date: Fri, 12 Feb 2021 14:12:49 -0500 > From: Wanda Norman <wanda.mnorman2...@gmail.com> > To: Nicolas Cadieux <njacadieux.git...@gmail.com> > Cc: qgis-user <qgis-user@lists.osgeo.org> > Subject: Re: [Qgis-user] Raster Calculator Error Questions > Message-ID: > <CAFN0wn0gq9wJY3=urkk0mhdujce_bvweowh2_l7hbxex6km...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Thanks Nicolas for the quick response. But I am still having issues. > > I did upgrade to the 3.16 version and I am still unable to write the > formula. I tried: ( "aspect@1" < = 90) OR ( "aspect@1" > = 270) - I get > Expression is not valid. As soon as I put anything other than "aspect@1" I > get a message that the expression is not valid. > > This is the first time using the raster calculator and it looks as if I > can't move forward with the lesson without this step. > > Any other suggestions? > > Thanks for your help! > Wanda > > > > On Fri, Feb 12, 2021 at 10:08 AM Nicolas Cadieux < > njacadieux.git...@gmail.com> wrote: > > > Hi, > > I have not used the raster calculator in a while but I am not sure about > > you use of the \. > > Examples in the user manual ( > > > https://docs.qgis.org/3.16/en/docs/user_manual/working_with_raster/raster_analysis.html#raster-calculator > ) > > use this as examples. > > > > ("elevation@1" < 50) * 1 + ("elevation@1" >= 50) * 2 > > > > > > I would try (expression 1) OR (expression 2). Layers names must be > placed > > between quotes ??. > > > > You could also update your QGIS version to 3.16. > > > > Nicolas Cadieux > > https://gitlab.com/njacadieux > > > > Le 12 f?vr. 2021 ? 09:09, Wanda Norman <wanda.mnorman2...@gmail.com> a > > ?crit : > > > > ? > > > > Greetings friends: > > > > > > > > I am working on lesson 7.3.5 in the User Guide / Manual (QGIS 3.10) ? > > Following along: Using the Raster Calculator. > > > > > > > > I am having difficulty with the calculation formula as indicated below: > > > > > > > > The manual states this formula should be used: > > > > Aspect@1 <=90 OR Aspect@1 >= 270 > > > > Which I am assuming is incorrect because a) I get an error when I run it; > > and b) when I set the parameters using the expression operators the > formula > > looks like this: > > > > ?Aspect@1? <=90 OR ?Aspect@1? >=270 > > > > However, I still get the error: > > > > Error parsing formula > > > > Execution failed after 0.02 seconds > > > > > > > > With some help ? I then tried this formula > > > > \?Aspect@1?\ <=90 OR \?Aspect@1?\ >=270 > > > > Which worked for this assignment. > > > > > > > > However, moving on to lesson 7.3.6 ? More criteria: which takes me to > > 21.12.2. Calculate slope (less than 2 and 5 degrees) > > > > I get the same error as above again. > > > > > > > > I am steadily working my way through the Manual and would appreciate any > > help. I am using QGIS version 3.10.9-A Coruna (64 bit) on a Windows PC. > > > > > > > > Thank you! > > > > Wanda Norman > > _______________________________________________ > > Qgis-user mailing list > > Qgis-user@lists.osgeo.org > > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.osgeo.org/pipermail/qgis-user/attachments/20210212/83089c60/attachment-0001.html > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > > ------------------------------ > > End of Qgis-user Digest, Vol 180, Issue 35 > ****************************************** > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >
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