ArcMap 10.3 Mosaic to New Raster produce a single color output

Pixel Type Problems: The pixel type is basically the DNA of your raster. It defines how much information each pixel can hold. If you’re not careful and set it wrong, you might end up squashing all the data into a tiny box, resulting in a single color. It’s like trying to pour a gallon of water into a pint glass – things are gonna get messy!

Raster Property Mismatches: Imagine trying to build a house with bricks of different sizes and shapes. It’s not going to work, right? Same goes for rasters. If your input rasters have different numbers of bands or bit depths, the mosaic tool gets confused, and you might get that dreaded single-color output.

Colormap Conundrums: Color maps can be tricky. If your rasters have different color maps, the mosaic tool needs to know how to handle them. Otherwise, you might end up with a weird color clash, or worse, a single, dominant color taking over.

Background Processing Gremlins: Sometimes, ArcMap’s background processing can throw a wrench in the works. It’s like having someone try to “help” you cook, but they just end up making things worse.

Just a Rendering Illusion?: Believe it or not, sometimes the data is actually correct, but ArcMap isn’t displaying it correctly!

Inspect Your Ingredients (Input Rasters): First things first, check the properties of each raster. Make sure they all have the same number of bands, the same bit depth (pixel type), and the same coordinate system. This is absolutely crucial. If the pixel sizes differ, resample them to a common size before you start mosaicking. Trust me, it’ll save you headaches later.

Set the Pixel Type Explicitly: In the “Mosaic to New Raster” tool, don’t leave the pixel_type parameter to chance! Manually set it to match your input rasters. Common types include 8_BIT_UNSIGNED, 16_BIT_UNSIGNED, and 32_BIT_FLOAT. Not sure what to pick? Check the properties of your input rasters – that’ll tell you.

Tame Those Color Maps: If your rasters have color maps, pay close attention to the “Mosaic Colormap Mode” parameter. You’ve got a few options here:

• FIRST: Uses the color map from the first raster.
• LAST: Uses the color map from the last raster.
• MATCH: Tries to find a common color map.
• REJECT: Ignores rasters with color maps.

Experiment! See which one gives you the best result. Sometimes it’s a bit of trial and error.

Banish Background Processing (Temporarily): If you suspect background processing is the culprit, disable it temporarily. Go to Geoprocessing > Geoprocessing Options in ArcMap and uncheck “Enable” in the “Background Geoprocessing” section. Then, run the tool again and see if it makes a difference.

Check Your Symbology!: This one has gotten me before. It may be that your raster is displaying as a single color because of the rendering settings. In the table of contents, right-click the mosaicked raster layer and select “Properties”. Go to the “Symbology” tab, and ensure that a proper stretch type is selected (e.g. Minimum-Maximum). Adjust the color ramp as needed.

Try a Different Output Format: Sometimes, the output format can be the issue. Try saving the mosaic to a different format, like TIFF or Esri Grid. You never know, it might just do the trick.

Mind the Gaps: No one likes a patchy mosaic. If you see missing sections, it could be a rendering issue or a problem with the tiling. Try recalculating the pyramids – that often helps.

Color Correct it: Use the Color Correction window to apply color correction to the mosaic dataset to create a seamless looking mosaicked image.