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How To: Mosaic multiband images using ArcGIS and Spatial Analyst

Summary

Steps to mosaic multiband images in ArcGIS using the Spatial Analyst extension (required).

Procedure

  1. Start ArcCatalog and navigate to the raster of choice.
  2. Right click on the raster and select Export > Raster To Different Format...
  3. Save as an ESRI GRID.
    [O-Image] Export raster dialog
    This process will create a grid for each band in the image. The grids will be distinguished by a "c + number" suffix. For example, image1 will export to image1c1, image1c2 and image1c3. A grid stack with the root name of the other output grids will also be created.
  4. Start ArcMap and add the grids representing the bands of data to a data frame.
  5. Select Raster Calculator from the Spatial Analyst pull-down menu
  6. Use the MOSAIC command in Raster Calculator to mosaic the data together.
    Here is an example of the syntax:

    Code:
    [Band1] = MOSAIC([ImageName1],[ImageName2],[ImageName3])


    Note:
    [Band1] is the name of the output grid; a permanent grid will be created on disk called Band1. This step will need to be done for each band.


    Note:
    ImageName1 refers to the output raster from band1 of the first image. ImageName2 and ImageName3 refer to the output rasters from the first band of images 1 and 2, respectively.

  7. Use the MAKESTACK command in the Raster Calculator to create a grid stack from the mosaiced bands. Here is an example of the syntax:

    Code:
    MAKESTACK newstack LIST [Band1] [Band2] [Band3]


    Note:
    "Newstack" will be the name of the output stack. There are no parentheses or commas used with this command in the Raster Calculator.


    Note:
    The word "LIST" should be omitted when using the MAKESTACK command in version 8.1.2

  8. Navigate to the directory containing the new grid stack in ArcCatalog.
  9. Right click on the grid stack and select Export. Choose Raster to MrSID if you need this format or Raster to Different Format. The Raster to Different Format utility will allow you to create TIFF's or ERDAS Imagine image files.

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