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How To: Merge multiple raster datasets into a new raster dataset in ArcMap

Summary

It is recommended to preserve the original raster datasets wherever possible, so the Mosaic tool and the Mosaic To New Raster tool with an empty raster dataset as the target dataset are the best choices to merge raster datasets. The Mosaic tool is used to mosaic multiple input rasters into an existing raster dataset. The existing raster dataset can be empty or it can already contain data. The tool is used to merge rasters that are adjacent and have the same cell resolution and coordinate system. Similar to the Mosaic tool, the Mosaic To New Raster tool is used to mosaic multiple input raster datasets. However, unlike the Mosaic tool, the Mosaic To New Raster tool saves the output mosaic in a new empty raster dataset which it creates on the fly.

The instructions provided describe how to merge multiple raster datasets into a new raster dataset using the Mosaic To New Raster tool in ArcMap. The following figure displays an example of raster datasets to be merged into one raster dataset.
 

Rasters for merging

Procedure

To merge two or more raster files together using the Mosaic To New Raster tool, follow the steps below.

  1. Determine the number of bands and pixel type of the raster files (right-click Table Of Contents > Properties > Source tab). The inputs must have the same number of bands and same bit depth.
The Source tab
  1. Open the Mosaic To New Raster tool by navigating to ArcToolbox > Data Management Tools > Raster > Raster Dataset.
    1. Insert the raster files.
    2. Select the output location.
    3. Give a name and extension to the output.
    4. Specify the pixel type.
    5. Specify the number of bands.
The Mosaic To New Raster tool
  1. Run the tool.
  2. The following is an example of an output of a merged raster:
Merged DEM raster files
Note:
This tool may take a while to run depending on the resolution of the images and their size.

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