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I'm trying to merge some DEMs downloaded from USGS. When I used ArcGIS 9.2 there was an expression to be used in raster calculator to do that. I used it again but, unfortunately, it doesn't work in ArcGIS 10.2.

What can I do?

I do not have the Production Contouring toolbar.

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17

Start by converting them to raster formats (assuming they are in DEM format to start with): enter image description here

then use the 'Mosaic to New Raster' tool to combine the different rasters into a single one: enter image description here

Make sure that they are in the same units before mosaicing them or they will look really odd when you stitch them together.

That's the basic approach I use, I'm assuming the DEMs you have are all in the same coordinate system/projection/units/cell size/etc. If not, make sure you get all the rasters into identical formats before you start, it will make your life a lot easier.

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  • Hi Kevin n Streppy, I had make sure that in my case the two DEM are identical formats. However, do you know why the resulted DEM has range value of 0 to 255? (Both the two source DEM have range 0 to more than 2000 m). Thanks before – Santosa Sandy Mar 3 '16 at 12:12
  • As a newbie to this tool, I had to poke around the Toolbox before finding the command, as the full path was cut off in the screenshot: ArcToolbox\Data Management Tools\Raster\Raster Dataset\Mosaic to New Raster – Bill Walker Feb 8 '18 at 3:18
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The range value issue of 0 to 255 that you are having is because of the pixel type being set to 8_BIT. TO have higher numbers set a higher bit value.

From ArcMap Tool Help

1_BIT —A 1-bit unsigned integer. The values can be 0 or 1.

2_BIT —A 2-bit unsigned integer. The values supported can be from 0 to 3.

4_BIT —A 4-bit unsigned integer. The values supported can be from 0 to 15.

8_BIT_UNSIGNED —An unsigned 8-bit data type. The values supported can be from 0 to 255.

8_BIT_SIGNED —A signed 8-bit data type. The values supported can be from -128 to 127.

16_BIT_UNSIGNED —A 16-bit unsigned data type. The values can range from 0 to 65,535.

16_BIT_SIGNED —A 16-bit signed data type. The values can range from -32,768 to 32,767.

32_BIT_UNSIGNED —A 32-bit unsigned data type. The values can range from 0 to 4,294,967,295.

32_BIT_SIGNED —A 32-bit signed data type. The values can range from -2,147,483,648 to 2,147,483,647.

32_BIT_FLOAT —A 32-bit data type supporting decimals.

64_BIT —A 64-bit data type supporting decimals.

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