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I am trying to create a slope map. I have many contour elevation files. I tried to use the slope tool in Arctoolbox, but it calls for raster files and I'm working with vector data. Any help with this will be greatly appreciated!

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Do you have access to the 3D Analyst extension? –  JWallace Jul 16 at 20:17
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3 Answers 3

You first need to make a raster DEM from your contours. That requires the Spatial Analyst extension, and uses the Topo to Raster tool (Spatial Analyst | Interpolation toolbox). That elevation raster can then be used as the input for the Slope tool.

Note that since this is an interpolation process, it is estimating the elevation values between the contour lines. That's simply a source of possible error to be aware of in subsequent analyses and/or interpretation of results, however.

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The topo to raster tool is intended for a hydrological DEM but that would probably suit here. You should really try to get more information: spot heights, lakes, creeks.. to feed the topo to raster tool for better results but still don't get your hopes up too high as DEM derived from contours will have some stripe effect from contours. The better the source, the better the results... oh, and if you find spot elevations remove them in close proximity to contours to avoid arguments, only use them for flat areas between contours. –  Michael Miles-Stimson Jul 16 at 22:16
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The other answers cover the Spatial Analyst extension. Another option is the 3D Analyst extension.

You can create a TIN from your contours, then convert the TIN to a raster, before calculating the slope.

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In order to make a slope map you need to work with raster data. You will need to make a raster tile (ie: DEM) from your contours. With the output raster you will then be able to make a slope map.

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