Identify Pixel Value From Raster Catalog

[RyanCoodey]

I never could understand why, but ArcMap has never been able to identify pixel values from rasters in a catalog, only stand alone raster datasets (there is a request for this at ideas.arcgis.com).  This is the same functionality in ArcGIS Server and REST...

I had posted this similar question in the Silverlight/WPF forums over a month ago, but didn't find a solution: http://forums.arcgis.com/threads/16335-Raster-Catalog-Identify-Image-s-Pixel-Value-(And-Legend-Not-S...

Our users really need this functionality and since it is more a limitation of the REST API, I thought I would ask here...

- From what I can see there is no way in REST to get access to an individual raster in the catalog, is this true?
- Is there no way to trick the REST API to treat the catalog layer as a standalone raster?  I am assuming REST can do an identify for pixel values on a raster dataset, please correct me if I am wrong.
- Is there no way to get access to the underlying connection info of the layer (SDE Feature Class)?  Then I could perform some ArcObjects in my WPF application on it.
- Any other ideas?

Thanks a lot for any help!!!

[WenxueJu]

You are very welcome. Happy new year and enjoy coding!

[RyanCoodey]

Well, I got the identify all working to get the pixel values and the time slider seems to be working with the mosaic too... but I realized there is another issue:

I had a raster from the original raster catalog with its classified renderer next to a raster in the new mosaic dataset (which btw references the same catalog) and I noticed the colors are a bit different, close, but different.  I triple checked the stretch function and the colormap file and it seems to all be correct as I would expect and as we discussed above. 

I have tried a number of changes to the mosaic settings without luck.  Such as only allowing one raster to be draw, not allowing mosaicing...  The output from the colormap function is 8-bit unsigned and I am using 32-bit RGB colors in the color map, ex.  211 255 190... Is this a problem?  I tried changing the output of the colormap function to 32-bit unsigned, but that made everything all black.
I don't think it is a problem with the bit depth though or any of the applied functions, because when I do an identify in ArcMap on an area that should be a certain color, it will show the RGB value which might be for green but there is actually red on the screen.  And there are pixels nearby that are indeed this same green that they should be.

Any ideas?  Hoping it�??s a simple setting I missed?

Thanks a lot!

[RyanCoodey]

Ok, I solved that problem... it was indeed my colormap... the maping values were off by one.

Now I am having some troubles working out identifying the pixel for only the currently visible raster (based off time).  Would be nice if the image service identify took a time extent.  Only way I can see to do this is in the mosaicRule to either set the FIDs to the visible raster or set the Where clause on the date fields.  Problem with this is in the Silverlight app I do not have access to the visible rasters info or its time field names...

[RaviNarayanan]

Ryan,

Image service Identify operation currently does not support time. We are planning to add this in 10.1.

thanks
Ravi

[RyanCoodey]

Good news, thanks a lot ravi! 

For the time being I am making a seperate Query operation with the TimeExtent to get the OID of the visible feature and then plugging it in the MosaicRule.

*EDIT* Another issue with the Identify on a mosaic dataset is that it does not obey the transformations assigned to the mosaic.  Visually the images are showing right, but when performing an identify they are off... i posted about this issue already here: http://forums.arcgis.com/threads/20948-Image-Service-Identify-Not-Obeying-Transformations

Thanks again!

[RaviNarayanan]

Thank you for reporting this. We have bug logged for Image Server to investigate this issue.

Another issue with the Identify on a mosaic dataset is that it does not obey the transformations assigned to the mosaic. Visually the images are showing right, but when performing an identify they are off... i posted about this issue already here: http://forums.arcgis.com/threads/209...ransformations

[AndreasWalter1]

Hey Ravi,

are there any news to the problems with the identify function for Image Server and Raster Catalog for version 10.4?

Thanks in advance!

[SteveLi]

In this thread, there is a identify sample privided by Wenxue.

http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/World/Temperature/ImageServer/identify?ge...

It takes > 40sec to run.  Is there a way to speed up the identify operation?  I know it's against over 1000 layers.  I am trying to add a chart to summary temprature change at a spot, it's taking too long to have a good user experience.

Thanks.