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Slope map generation and customization

July 28 2010 | 0 comments
Categories: Symbology

Hi

I am analyzing bathymetric Raster maps. Now I'd like to generate from them slope maps, depicting in the most representative way slope values on each of Raster map.

Each Raster bathy map has different slope values after processing with Spatial Analyst. Let me say that slope values vary here from 0 to 60 degree (in some example from 0 to 9 degree, more flat seabed areas).

How one shall reclassify each slope map in order to present the slope value in the most coherent way? Is there any guidance/best practice document for it? How many intervals are to be asset?

I may assume reclassifying the slope map as follow

Legend
Slope map (in degree)

0-1
1.1-2
2.1-3
3.1-4
4.1-5
5.1-6
6.1-7
7.1-8
8.1-9
9.1-10
10.1-15
15.1-20
20.1-30
30.1-40
40.1-50
50.1-60
>60.1

But this is my interpretation of the slope map classification. Which classification method the Cartographic Professionals would use in such (and other) cases.


I would be more than happy being granted some links to the source of information which describes/shows in detail generation and customization of slope maps.

Thank you

Mapping Center Answer:

The reclassification of the slope values depends entirely upon the use fo the map/data.  Usually there are some critical values for slope when used for such things as land use management, watershed modeling, landslide prediction, and so on.  The classification of these values for cartographic purposes only really doesn't make sense unless it is related to how the map will be used.  Therefore, it would be best to research the literature about the type of phenomena that the map is related to and select classes from those types of applications.

Note that we did write a blog entry about creating an aspect-slope map that shows simultaneously the slope and aspect of the surface.

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