topic Re: (again): "reclassify" introduces an error! why? in ArcGIS Spatial Analyst Questions

(again): "reclassify" introduces an error! why?

JamalNUMAN — Wed, 24 Aug 2011 14:44:07 GMT

(again): "reclassify" introduces an error! why?

please, see the attached image that shows my question

for my raster, i needed to reclassify the raster into 5 classes, but the reclassified raster gives an error!!!! why?

why this problem happens?

how to automatically avoid this problem?

regards

Jamal

Re: (again): "reclassify" introduces an error! why?

Anonymous User — Fri, 26 Aug 2011 14:15:33 GMT

Original User: Tarun_Jaiswal

Hi Jamal,

Please convert your img file to tiff or grid format using Copy Raster tool.
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001700000094000000
and then reclassify the raster again.

Thanks.

Re: (again): "reclassify" introduces an error! why?

JamalNUMAN — Fri, 26 Aug 2011 16:31:56 GMT

Hi Jamal,

Please convert your img file to tiff or grid format using Copy Raster tool.
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001700000094000000
and then reclassify the raster again.

Thanks.

Thank you for the answer Tarun_Jaiswal.

i tried it but didn't work. please, see the attached image

why this error happens?

regards

Jamal

Re: (again): "reclassify" introduces an error! why?

Anonymous User — Fri, 26 Aug 2011 18:55:57 GMT

Original User: erictrice

Jamal,

In the Reclassify tool, click the button called "Precision" and send a screenshot of your settings. As the warning is indicating (not an error message) you may need to make adjustments to the precision, or maybe you just need to get it back to the defaults if you already made adjustments. I calculated an NDVI raster and reclassified it without any warnings. Only after fiddling with the settings and reducing the significant digits to only a couple was I able to repro the warning messages your are getting.

Regards,
Eric

Re: (again): "reclassify" introduces an error! why?

JamalNUMAN — Fri, 26 Aug 2011 19:13:07 GMT

Jamal,

In the Reclassify tool, click the button called "Precision" and send a screenshot of your settings. As the warning is indicating (not an error message) you may need to make adjustments to the precision, or maybe you just need to get it back to the defaults if you already made adjustments. I calculated an NDVI raster and reclassified it without any warnings. Only after fiddling with the settings and reducing the significant digits to only a couple was I able to repro the warning messages your are getting.

Regards,
Eric

thank you for the help erictrice.

Attached is the screen shot for the precision.

the problem that the reclassification of "image1_ndvi.img" (attached in the previous post) generates this warning!!!!!

what's wrong with it?

what is the default?

regards

Jamal

Re: (again): "reclassify" introduces an error! why?

Anonymous User — Fri, 26 Aug 2011 22:30:34 GMT

Original User: erictrice

Jamal,

Try increasing the significant digits to 9. If that doesn't work, check the option to use "Format" precision. For your min use -1.0 and for the max use 1.0. This worked for me. Optionally you could use the real min/max obtained from the layer properties > source tab > statistics section. Those are the real min/max values. The stats in the classification dialog are estimates.

Note, your screenshot is the default. Everytime you open the tool it should have those values. Any changes will only 'stick' if you make the changes, run the tool, then run the tool again from the Results window.

Regards,
Eric

Re: (again): "reclassify" introduces an error! why?

JamalNUMAN — Sat, 27 Aug 2011 08:19:15 GMT

Jamal,

Try increasing the significant digits to 9. If that doesn't work, check the option to use "Format" precision. For your min use -1.0 and for the max use 1.0. This worked for me. Optionally you could use the real min/max obtained from the layer properties > source tab > statistics section. Those are the real min/max values. The stats in the classification dialog are estimates.

Note, your screenshot is the default. Everytime you open the tool it should have those values. Any changes will only 'stick' if you make the changes, run the tool, then run the tool again from the Results window.

Regards,
Eric

thank you Eric.

sure, if i change MANUALLY the min and max, then it should work!!!!

my point is why ArcGIS is not able to get the true min and max automatically????!!!!! given that ArcGIS knows the actual min and max with right digital numbers!!!!!!

why we are involved in such problem as user?

my question is still valid:

how to classify AUTOMATICALLY this raster?

all the best

Jamal

Re: (again): "reclassify" introduces an error! why?

Anonymous User — Thu, 01 Sep 2011 17:08:21 GMT

Original User: erictrice

Hi Jamal,

Sorry I haven't had a chance to get back to you sooner. I believe what you're experiencing is a data/version specific bug in the software. I would not expect any user to type the min/max (unless it's a workaround) to reclassify some data. I was only attempting, with that suggestion, to get you a reclassified raster that you could continue working with.

In an earlier post, I mentioned that I created a NDVI raster (from a single Landsat scene) using the Raster Calculator and was able to reclassify it without having to type the min/max or make any changes to the precision dialog. I actually had to intentionally mess it up to get the same warning as you. By default it was working as you would expect it to. The main difference between you and me though, is I was using 10.1 Beta version, and we have different (yet similar) data.

If you have the tutorial data installed you could use the same Landsat scene I used, to create your own NDVI raster and attempt to reclassify it to see if you get the error in 10.0. See attached for data location. If you can't repro the warning messages with the tutorial data, then it's probably specific to the raster values in your real dataset, and you might consider sending it to your local Esri distributor so they can forward it to us as part of a bug report.

Best Regards,
Eric

Re: (again): "reclassify" introduces an error! why?

JamalNUMAN — Sat, 03 Sep 2011 15:15:03 GMT

Hi Jamal,

Sorry I haven't had a chance to get back to you sooner. I believe what you're experiencing is a data/version specific bug in the software. I would not expect any user to type the min/max (unless it's a workaround) to reclassify some data. I was only attempting, with that suggestion, to get you a reclassified raster that you could continue working with.

In an earlier post, I mentioned that I created a NDVI raster (from a single Landsat scene) using the Raster Calculator and was able to reclassify it without having to type the min/max or make any changes to the precision dialog. I actually had to intentionally mess it up to get the same warning as you. By default it was working as you would expect it to. The main difference between you and me though, is I was using 10.1 Beta version, and we have different (yet similar) data.

If you have the tutorial data installed you could use the same Landsat scene I used, to create your own NDVI raster and attempt to reclassify it to see if you get the error in 10.0. See attached for data location. If you can't repro the warning messages with the tutorial data, then it's probably specific to the raster values in your real dataset, and you might consider sending it to your local Esri distributor so they can forward it to us as part of a bug report.

Best Regards,
Eric

Thank you Eric for the comprehensive answer.

The issue here is the reclassification not the NDVI! I expected that the ArcGIS can reclassify any raster AUTOMATICALLY!!! by the way, i got the NDVI (fro the image) from ERDAS 2011 then added this NDVI to ArcGIS for further analysis!

what about ArcGIS 10.1? when will it be available? and how come the ArcGIS 10.0 is full of bugs that much even with the very basic issues?

very much appreciated

regards

Jamal

Re: (again): "reclassify" introduces an error! why?

Anonymous User — Tue, 06 Sep 2011 21:28:27 GMT

Original User: pyadav1

Thank you Eric for the comprehensive answer.

The issue here is the reclassification not the NDVI! I expected that the ArcGIS can reclassify any raster AUTOMATICALLY!!! by the way, i got the NDVI (fro the image) from ERDAS 2011 then added this NDVI to ArcGIS for further analysis!

what about ArcGIS 10.1? when will it be available? and how come the ArcGIS 10.0 is full of bugs that much even with the very basic issues?

very much appreciated

regards

Jamal

Hi Jamal,
I agree that the reclassify tool should automatically read min/max. I tried to reproduce this issue with similar data in ArcGIS 10 SP 2; however, I have not been able to reproduce the behavior you are experiencing. It could be possible that this behavior is either a data or a computer specific issue. Could you please try to see if you can reproduce this behavior with other rasters and/or on other computers?

ArcGIS 10.1 is scheduled to be released in the first quarter of 2012. ArcGIS 10.1 Beta 1 is currently available. Domestic (USA) users need to be current on maintenance and approved by the maintenance contact for their organization to participate. International users need to be nominated by their distributor.

We greatly appreciate our users�?? feedbacks and try our best to fix issues that we are aware of or our customers brought to us. We are sorry that you encounter issues in ArcGIS 10 and we will be glad to work with you to identify those issues and fix them in next service pack/release. You could contact Esri Support Services (in your case, I guess Esri UK) to report bugs.

Thank you for your feedback.

Best regards,
Pavan

Re: (again): "reclassify" introduces an error! why?

JamalNUMAN — Wed, 07 Sep 2011 15:23:39 GMT

Hi Jamal,
I agree that the reclassify tool should automatically read min/max. I tried to reproduce this issue with similar data in ArcGIS 10 SP 2; however, I have not been able to reproduce the behavior you are experiencing. It could be possible that this behavior is either a data or a computer specific issue. Could you please try to see if you can reproduce this behavior with other rasters and/or on other computers?

ArcGIS 10.1 is scheduled to be released in the first quarter of 2012. ArcGIS 10.1 Beta 1 is currently available. Domestic (USA) users need to be current on maintenance and approved by the maintenance contact for their organization to participate. International users need to be nominated by their distributor.

We greatly appreciate our users�?? feedbacks and try our best to fix issues that we are aware of or our customers brought to us. We are sorry that you encounter issues in ArcGIS 10 and we will be glad to work with you to identify those issues and fix them in next service pack/release. You could contact Esri Support Services (in your case, I guess Esri UK) to report bugs.

Thank you for your feedback.

Best regards,
Pavan

Thank you for the answer Pavan.

Th notes and information you have provided are quite useful.

regards

Jamal

Re: (again): "reclassify" introduces an error! why?

Anonymous User — Thu, 13 Oct 2011 20:18:45 GMT

Original User: pversteeg

Greetings,
I want to echo Jamal in my frustration with his reclassify problem. I am attempting to reclassify a raster for a LANDFIRE data update and have encountered the same problem with warning and error messages about the precision field and the default max and mins. I tried making sure the raster was symbolized correctly, had statistics calculated, etc., but with no success. I also tried running the reclass on a colleagues machine with the same version of 10.0. I am going to try reclassifying on a machine with 9.3 and will see how that goes. If I have success I'll let you all know. Thank you!

PVS

Re: (again): "reclassify" introduces an error! why?

PieterVer_Steeg — Fri, 14 Oct 2011 17:33:48 GMT

Hello again,
I believe the source of the warnings we were getting in reclassifying our raster (this could or could not be the same source for Jamal's troubles) was that somehow the raster pixel depth (8/16/32 bit signed, unsigned, etc.) had been changed so that the reclass we were trying to pull off (the new values we were assigning) was not supported in the format the raster was in.

What we did to change this was go back a few processing steps and make sure all statistics had been calculated and that our raster that we eventually wanted to reclass had the correct pixel depth. Somehow along the way the pixel depth was changed to 8-bit unsigned and in order to reclassify how we wanted we needed 16-bit signed.

This may help, but likely the issue has already been resolved,

PVS

Re: (again): "reclassify" introduces an error! why?

Anonymous User — Sun, 16 Oct 2011 19:06:10 GMT

Original User: Jamal432@gmail.com

Hello again,
I believe the source of the warnings we were getting in reclassifying our raster (this could or could not be the same source for Jamal's troubles) was that somehow the raster pixel depth (8/16/32 bit signed, unsigned, etc.) had been changed so that the reclass we were trying to pull off (the new values we were assigning) was not supported in the format the raster was in.

What we did to change this was go back a few processing steps and make sure all statistics had been calculated and that our raster that we eventually wanted to reclass had the correct pixel depth. Somehow along the way the pixel depth was changed to 8-bit unsigned and in order to reclassify how we wanted we needed 16-bit signed.

This may help, but likely the issue has already been resolved,

PVS

Thank you Pieter for the answer.

I couldn't know how can I play with the pixel depth!

i tried to reclassify my image into 3 classes but the classification produces 4 classes!
the screen shots are attached. the image is in:

https://skydrive.live.com/?wa=wsignin1.0&sa=966370302#!/?cid=933fce186397e357&permissionsChanged=1&id=933FCE186397E357%21171

regards

Jamal