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Mosaic 8bit pseudo colour tiffs

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12-21-2018 11:03 PM
NeilAyres
by MVP Alum
MVP Alum
‎12-21-2018 11:03 PM

I have a collection of scanned map images (50k topo series of South Africa).

Each image is scanned as 8bit unsigned pseudo colour tiffs. They have individual colour maps.

Many moons ago, I created a mosaic of these and it worked like a bomb.

I haven't looked at this data for a while so when I opened it the other day, and it looked all ucky, I thought, no probs, maybe something has broken the mosaic, I'll just rebuild it. Won't take long.....

Well this has become more problematic than I thought. Currently on v10.5.1.

Turns out that mosaic now doesn't recognise this format automatically. When I load them in, it just reverts to stretched grey scale, ignoring each colour map.

So, now we have options for lots of different types of imagery, but this, possibly oldest way of map scanning, no longer works with mosaic!!!

Anybody have an idea.

But not this answer :

arcgis desktop - Creating Mosaic Dataset in ArcMap with Colormap as renderer or adding Colormap afte... 

There are +1900 images. Can't export each one!!

Thanks,

Neil

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2 Replies
NeilAyres
by MVP Alum
MVP Alum
‎01-21-2019 11:55 PM

Bump....

Anyone at esri got a thought about this?

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NeilAyres
by MVP Alum
MVP Alum
‎01-31-2019 01:42 AM

Reply from esri. Apparently fixed in next release 10.7

This is Amrita, with ESRI Support Services, writing in reference to the case #02257124. I have taken the ownership of this issue and will be working with you.

I have researched on the issue and found the following:

A defect for the issue but this issue has been resolved and fixed for the next release 10.7. 

Public Explanation: Another easier workaround would be to change the re-sampling method on the image display. Right click on the image in the Table of Contents. Go to the layer properties. Under the Display tab, change the 'Re-sample during display using' to Nearest Neighbor. This resolves the issue and not allow current users to create a copy of the all the raster (using Copy Raster) when using large amounts of data.

Workarounds:

  1. Create a copy of the raster (using the Copy Raster tool), make sure to check "Color-map to RGB". Keep the rest of the parameters as default.
  2. Add the copied raster to a mosaic dataset. The color map is not lost by building footprints on this mosaic dataset.

Could you also check with the re-sampling type that was causing the final output after the build footprint,thus showing a bad image?