Add Rasters to Mosaic Dataset

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04-18-2024 12:33 PM
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JackFilbrandt
New Contributor

Hi

I'm fairly new to ArcGIS Pro (using 3.2.2) and I'm working with multiple DTM rasters in the form of .tif tiles (5 by 5 km) with floating point z values. Each individual raster has a spatial resolution of 1 m and vertical resolution said to be 15 cm (but there are 6 decimal places!) I want to keep the detail.

When I load the .tifs, each individual tile has its own min and max value, so the colourmaps don't match across the boundaries. I want to see a common colourmap across all the tiles from the highest to the lowest value in the dataset. I also need to do some processing (slope, aspect amongst others) and don't want to be selecting multiple tiles every time I run raster functions. I've tried several options (including Mosaic to Raster) and I'm currently working on creating a mosaic dataset. 

I'm running a trial and with Add Rasters to Mosaic Dataset I select Calculate statistics and Build Raster Pyramids in Raster Processing (with Maximum Levels set to 6 and Maximum cell size set to 1 - default is 0 but that didn't feel right - and Minimum Rows and Columns left at 1500). In Mosaic Post-Processing I toggle on Build Thumbnails, Update Overview and Estimate Mosaic Dataset Statistics. When I created the Mosaic Dataset to put these rasters in, I set the Pixel Type to 32 bit signed (and Number of Bands to 1).

The output raster is successfully created but the Value returned (for symbology and in the raster) is an integer. I really want to keep the higher resolution. In addition, the min and max of the combined raster (of 2) don't match the min and max of the input (the min is higher than the true min and the max is lower than the true max by up to 20 m on a range of 600 m).

What am I missing in the processing steps to retain the floating point and the true min-max? Should I not use Mosaic Dataset to retain the detail/resolution? Is there another workflow to keep the detail to "Merge" or "Union" the rasters?

Thanks

Jack

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