topic Re: Mosaic to New Raster gives different values in Data Management Questions

Mosaic to New Raster gives different values

AlisaMorrison — Wed, 29 Aug 2012 14:42:45 GMT

Hi,

I am mosaicking several rasters to a new raster and when completed, the new mosaicked raster has different values than the original rasters. Any suggestions?

Re: Mosaic to New Raster gives different values

TimothyHales — Fri, 31 Aug 2012 13:38:18 GMT

Are these single band or 3 band imagery? What is the pixel type and bit depths of the input rasters and the output raster? Are you comparing the range or the individual pixels? How far off are the values?

Re: Mosaic to New Raster gives different values

AlisaMorrison — Mon, 24 Sep 2012 18:13:54 GMT

Are these single band or 3 band imagery? What is the pixel type and bit depths of the input rasters and the output raster? Are you comparing the range or the individual pixels? How far off are the values?

They are single band with continuous signed integers. (32 bit) The values are off by random amouts varying from being exactly the same to being off by more than double. I'm calculating solar radiation and starting with values like 250,000 so here are some examples. (value of original raster, value of mosaicked raster)

(140936,126618)
(271121,261405)
(93114,176000)
(124012,134030)
(177773,126547)
(123345,241540)

I've also tried changing the NoData values to 0 and that didn't work either. I"m at my wits end.

Re: Mosaic to New Raster gives different values

EricRice — Fri, 28 Sep 2012 14:54:27 GMT

Hi Alisa,

Do the rasters all have the same underlying grid? In other words, do the rasters that are going into the mosaic, all have perfect cell alignment? If they don't you should expect the value to change somewhat because they will be resampled. What resampling do you have set in your environments? Also, is there any overlap between the inputs? What options were set in the Mosaic Operator parameter?

If you have support, you should open an incident so an analyst can have a look.

Best,
Eric

Re: Mosaic to New Raster gives different values

AlisaMorrison — Mon, 01 Oct 2012 14:40:21 GMT

Hi Alisa,

Do the rasters all have the same underlying grid? In other words, do the rasters that are going into the mosaic, all have perfect cell alignment? If they don't you should expect the value to change somewhat because they will be resampled. What resampling do you have set in your environments? Also, is there any overlap between the inputs? What options were set in the Mosaic Operator parameter?

If you have support, you should open an incident so an analyst can have a look.

Best,
Eric

Hi Eric,

All the rasters have the same underlying grid and the same cell alignment, they do not overlap at all. I tried all the different mosaic options and have given up. I have tried everything I can think of to make this work and I think there is some bug in the program.

Re: Mosaic to New Raster gives different values

EricRice — Mon, 01 Oct 2012 15:37:44 GMT

What version? Support is the best option at this point. They can get your data to repro the issue and submit a defect.

Best,
Eric