topic Re: Wrong colors in raster catalog (mosaic) in Data Management Questions

Wrong colors in raster catalog (mosaic)

DavidElies — Tue, 20 Apr 2010 23:12:13 GMT

I apologize if this has been asked before, but I can't find my issue in the fora. I have some aerial images (LandSat, I believe) and I want to mosaic them, but when I do, the colors keep changing. The images do not overlap. I don't know enough about this software or its processes to figure out what's going on. I would appreciate any help in determining what's happening or how I can keep the colors of the original image rasters when they are mosaicked (or combined in a catalog). Thanks!

Wrong colors

EricRice — Fri, 23 Apr 2010 20:16:17 GMT

Its just a shot in the dark without seeing the data, but it sounds like your original data didn't have statistics and when you mosaic the tiles the software generates stats. Try taking your mosaic in ArcMap and go to Symbology tab. The stretch type probably says 'Standard Deviations'. Switch the type to 'None'. Does your mosaic now look more like you expect?

Re: Wrong colors

ForteConsulting — Thu, 12 Jul 2012 20:50:01 GMT

Its just a shot in the dark without seeing the data, but it sounds like your original data didn't have statistics and when you mosaic the tiles the software generates stats. Try taking your mosaic in ArcMap and go to Symbology tab. The stretch type probably says 'Standard Deviations'. Switch the type to 'None'. Does your mosaic now look more like you expect?

Hi there. I realize this thread is two years old now, but thought I would try and resurrect it. The scenario you describe (quoted above) is exactly what I am experiencing. Is there any way of correcting the mosaic dataset to accurately represent the colour in the source image?

Thanks.

Cam

Re: Wrong colors in raster catalog (mosaic)

GeospatialTechnology — Mon, 16 Jul 2012 13:53:42 GMT

You need to right click on the image name in the �??Table of Contents�?? again and select �??Properties�??.

Click on the �??Symbology�?? tab and then click on the drop down menu next to �??Type:�?? Change this from �??Standard Deviations�?? to �??None�?? then click okay.

Re: Wrong colors in raster catalog (mosaic)

ForteConsulting — Mon, 16 Jul 2012 17:30:08 GMT

Thanks for the reply Mark. I'm looking for a way of modifying the source mosaic dataset properties so that I don't have to alter the symbology in ArcMap. Any ideas?

Re: Wrong colors in raster catalog (mosaic)

GeospatialTechnology — Tue, 17 Jul 2012 07:59:56 GMT

No thats a bit beyond my abilities I'm afraid. However if you do find a solution please let me know as I would be interested in finding out myself.

Re: Wrong colors in raster catalog (mosaic)

JaroldHolland-Hibbert — Wed, 18 Jul 2012 19:10:03 GMT

yppmark,

You may want to try one of the following:
1) removing the statistics (if these were generated for your mosaic).
or
2) using the Colour Balance Mosaic Tool to create a second/alternate colour balanced mosaic (using the statistics you have generated).

I recommend testing the visual impacts on a sample mosaic first.

I use both solutions in my work, however, in this case you may want to try Solution 1 - remove statistics. You can recalculate statistics if you need them. However, depending on the size of your mosaic, this process may take a long time to complete.
Solution 2 uses statistics to achieve better colour balance across the mosaic area (e.g., you have imagery from two different Municipalities flown the same year, but a month apart). You can play around with the options to move both datasets to an acceptable middle ground.

I've found that clients generally prefer to view a mosaic without statistics generated as this appears to be more representative of the original base data. Depending on your workflow, you may not need statistics; statistics are however required if you wish to manipulate the imagery pixel values.

Removing statistics
Right-click the raster dataset or mosaic dataset in ArcCatalog and click Properties.
Scroll to the Statistics section on the General tab.
Click the Options button and click Clean Statistics.
The statistics are removed and the status is reported in this section of the dialog box.

Disable Statistics when Creating Mosaics
When building mosaics you may wish to turn off the statistics generation process. Statistics are generated by the default settings set in the mosaic tool.
You can disable this in Environment Settings
Raster Storage
Raster Statistics (clear the check box for Calculate statistics).

Color Balance Mosaic Tool
See Data Management Tools -> Raster -> Mosaic dataset ->Colour Balanace Mosaic Dataset

Cheers,
Jarold

Re: Wrong colors in raster catalog (mosaic)

AbbyParish — Wed, 31 Jul 2013 13:25:53 GMT

You need to right click on the image name in the �??Table of Contents�?? again and select �??Properties�??.

Click on the �??Symbology�?? tab and then click on the drop down menu next to �??Type:�?? Change this from �??Standard Deviations�?? to �??None�?? then click okay.

Thank you so much! I have been struggling with this same problem for a days. I had added the image multiple times with no problems and than one time it just came in black and I could not for the life of me figure out why. This fixed it and was exactly what I needed this morning!

Thanks!