nav[aria-label="Primary Navigation"] { padding: 0; & ul { list-style: none; width: 100%; display: flex; flex-direction: row; justify-content: start; align-items: start; gap: 30px; padding: 0; & li { margin: 0; } & ul li { list-style: none; } } }

Spatial Analyst (Raster Calculator): 'focalmean' no more?

MatthewRobinson

Hi,

I have a simple expression that worked great in the 9.x Raster Calculator to interpolate NoData values, but am having all kinds of trouble in 10:

dem1 = con(isnull([dem0]), focalmean([dem0], rectangle, 3, 3, data), ([dem0]))

Part of the problem is that con, isnull, etc. are now case-sensitive (Con, IsNull), but the most recent error message tells me that 'focalmean' is not recognized.

Any help 'modernizing' this expression would be hugely appreciated. Thanks!

-Matt

Trouver plus de publications taguées avec

Accepted answers

All comments

DanPatterson_Retired

if it is indeed case-sensitive, check the online help for the syntax (FocalMean???)
Break the operation into steps using tool in arctoolbox to see if you can get it to work.

also, you last expression ([dem0]) doesn't need the brackets ()

MatthewRobinson

Thanks Dan. I checked with the Arc10 Resource Center (URL: http://help.arcgis.com/EN/ArcGISDesktop/10.0/Help/00q8/00q80000006m000000.htm) for help with the syntax and case but unfortunately it's still not working:

Con(IsNull([point2ras]), FOCALMEAN ([point2ras] , RECTANGLE , 3 , 3, data), [point2ras])

When I run the expression with that structure, Spatial Analyst returns an error saying that the name of the input raster is not defined. I inserted "" around the layer name, re-ran it, and got a different error ['expected a raster or layer name']. I've attached a screen-capture of the error messages, for reference.

Any other suggestions?

Thanks,
Matt

SpatAnlst_errors.jpg

EricRice

Hi Matt,

The FocalMean command you're familiar with is not available in the new raster calculator. The documentation you pointed to is wrong and I will submit a defect to have it changed. To accomplish this task you need to use FocalStatistics with the mean statistic type within your Con statement.

It should look like this:
**unspecified**= Con(IsNull("point2ras"),FocalStatistics("point2ras",NbrRectangle(3,3),"MEAN"),"point2ras")

Where **unspecified** is my output name and i'm using a 3 x 3 rectangular neighborhood.

You may find this link helpful as it discusses differences between 9.x and 10.
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Comparing_Map_Algebra_between_9_x_and_10/00p600000018000000/

What is Map Algebra (in 10)
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/What_is_Map_Algebra/00p600000002000000/

Let me know if this helps.

Regards,
Eric

DanPatterson_Retired

this change apparently affects all "focal" statics types, see
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z000000qs000000.htm
for the correct syntax for all types

MatthewRobinson

Hi Eric and Dan,

Both you guys, thanks so much for your help!! The new expression worked great, and I really appreciate the links to the "What's New" between 9x and 10.

Best,
Matt

AndyRitchie

How do I submit a "defect"?

The changes made to the Focal Statistics don't even make sense. In addition to reducing the flexibility of the software to users (it's ok if there's more than one way to do something), it makes it harder to type in a simple map algebra statement.

I think this is a great illustration of what's wrong with ESRI's "update" strategy, and why people are repeatedly frustrated and alienated by ESRI every time an update breaks things. I am pretty adaptable, so it's not that big a deal to me, but I am also one of only two people who's been willing to upgrade to 10 in my division so far - and the other one said today that she's switching back.

What was the reason to add the 'Nbr' prefix to every neighborhood shape? Other than adding three more letters to type every time I enter a statement into the raster calculator this seems pointless. I know it's a neighborhood, just like I know that a circle is a circle without having to call it ShapeCircle.

oh, whoops. Is there somewhere I am supposed to put rants?
(this post was useful btw, at least I figured out how to change my syntax)

JamalNUMAN

it didn't work!!!!

help, please

Thanks Dan. I checked with the Arc10 Resource Center (URL: http://help.arcgis.com/EN/ArcGISDesktop/10.0/Help/00q8/00q80000006m000000.htm) for help with the syntax and case but unfortunately it's still not working:

Con(IsNull([point2ras]), FOCALMEAN ([point2ras] , RECTANGLE , 3 , 3, data), [point2ras])

When I run the expression with that structure, Spatial Analyst returns an error saying that the name of the input raster is not defined. I inserted "" around the layer name, re-ran it, and got a different error ['expected a raster or layer name']. I've attached a screen-capture of the error messages, for reference.

Any other suggestions?

Thanks,
Matt

nodataClip_25.jpg

errorClip_25.jpg

EricRice

Hi Jamal,

I reviewed your screenshot and you are specifying FOCALMEAN which is not a command in map algebra at 10.0. Please review my earlier post wherein I provide the syntax to use at 10.0. i.e. FocalStatistics

Regards,
Eric

JamalNUMAN

Thank you for the answer Eric.

i'm trying to replace the nodata cells with the 3x3 average window but didn't work

please, see the attached images

what might be wrong?

thank you

regards

Jamal

Hi Jamal,

I reviewed your screenshot and you are specifying FOCALMEAN which is not a command in map algebra at 10.0. Please review my earlier post wherein I provide the syntax to use at 10.0. i.e. FocalStatistics

Regards,
Eric

erroecalClip_24.jpg

expressinClip_26.jpg

EricRice

Jamal,

Your expression is using �??wt�?� but your layer name is �??wt1�?�.

Eric

JamalNUMAN

thank you ERIC. it did work.

now, how to say that it is solved?

appreciated

Jamal

Jamal,

Your expression is using �??wt�?� but your layer name is �??wt1�?�.

Eric

ElizabethGraham

Hi,

I have a suggestion that might help you create a valid map algebra expression.

1) To launch the Python window, click the Python Window button on the Standard toolbar, or from the Geoprocessing drop-down menu, click Python window.

2) Type the following expression, do not copy and paste. As you are typing you will see that drop down lists appear, auto completion is available, and help* shows up in the other panel to guide you in creating expressions with valid syntax.

>>> from arcpy.sa import *
>>> m2w = Con(IsNull("wt1"),FocalStatistics("wt1", NbrRectangle(3,3),"MEAN"),"wt1")

3) At the end of the expression click �??enter�?? to execute the expression.

For more on using the Python window:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/What_is_the_Python_window/002100000017000000/

*Note: If you don�??t see the help right click in the window, select a Help Placement (ie Bottom) and adjust the window panes until you can see the help.

Py_Window _Exp3.png

Py_Window _Exp2.png

AdamStencek

Hi Matt,

The FocalMean command you're familiar with is not available in the new raster calculator. The documentation you pointed to is wrong and I will submit a defect to have it changed. To accomplish this task you need to use FocalStatistics with the mean statistic type within your Con statement.

It should look like this:
**unspecified**= Con(IsNull("point2ras"),FocalStatistics("point2ras",NbrRectangle(3,3),"MEAN"),"point2ras")

..........

Eric, I was currently solving this problem why it doesnt work for like 2 hours. Thanks alot for helping me!

curtvprice

Eric, I was currently solving this problem why it doesnt work for like 2 hours. Thanks alot for helping me!

Elizabeth posted some very good tips above on getting the syntax right in the 10x Raster Calculator tool. If her suggestions don't help, feel free to post more details!

Rejoindre la conversation

Les membres connectés peuvent publier, suivre les mises à jour, et plus encore. Nouveau ici ? Inscrivez-vous gratuitement.

Liens rapides

Community Help
Find useful guides, FAQs, and documents to help you navigate and make the most of Esri Community.