topic Re: slope percent symbology in Mapping Questions

slope percent symbology

deleted-user-MS0lE1F_0-sy — Thu, 01 Oct 2015 14:17:17 GMT

I might be over thinking this but how do I get my slope, created using percent_rise output, to classify by the actual %?

The way I understand using the Classified Symbology it classifies by the percentile of my values range for the raster, NOT the percent slope. So how do I get it to symbolize by the actual percent rise value?

Re: slope percent symbology

ChrisDonohue__GISP — Thu, 01 Oct 2015 15:36:10 GMT

I think if you play with the Symbology settings you can define it the way you want. in the Layer Properties window, click on the Classify button. This will bring up the Classification window. In this Window try altering the Classification and see which method produces what you want. I suspect in your case it will be "Equal Interval". Another option is to choose "Defined Interval" and then type in manually the break values you want in the "Break Values" pane in the lower right.

Chris Donohue, GISP

Re: slope percent symbology

deleted-user-MS0lE1F_0-sy — Thu, 01 Oct 2015 16:08:20 GMT

I think I was just over thinking it. The reason is because the slope raster does not match up with the topo that was generated using the same raster and I don't know why.

Re: slope percent symbology

curtvprice — Sat, 03 Oct 2015 05:10:32 GMT

What do you mean by "not matching up?"

Is this a situation where the extent is set from another dataset or the current display extent without a snap raster specified?

Re: slope percent symbology

deleted-user-MS0lE1F_0-sy — Mon, 05 Oct 2015 11:05:48 GMT

No the extent was good, the results were ok but you could see it was missing a lot for the range I wanted of steep slopes. When looking at and calculating the slope from the contours and comparing that to the slope calculated using the tool it did not match up. I figured out that the Raster cells were just too big (30m), I got the cell size down to 3m and the results were a lot better.

Re: slope percent symbology

curtvprice — Tue, 06 Oct 2015 00:43:06 GMT

Yes, it is important to make sure the environment is doing what you want. Setting the cell size and snap raster can be critical to get correct results, as you discovered.

Re: slope percent symbology

AnthonyWhaley — Thu, 05 Dec 2019 17:44:10 GMT

Jumping into this conversation here.

Your project may be over now, but...I would suggest checking your sampling technique and pyramids. Both should be set to bilinear or cubic for continuous data like elevation, slope, etc. The nearest neighbor sampling can be used for nominal raster datasets like landcover.

This typically messes with how my data is displayed.