topic Re: Avalanche Hazard Mapping without vegetation in ArcGIS Pro Questions

Avalanche Hazard Mapping without vegetation

SMangum — Fri, 11 Mar 2022 08:16:09 GMT

I need to find the slope areas A) between 28º and 55º, B) contain an abrupt change of more than 10º, C) are more that 625 m2 in area, and D) are adjacent to glaciers

VERSION: ArcGIS Pro 2.9.2

INITIAL LAYERS: DEM_Slope, Glaciers_Raster

This is the workflow I have put together:

Slope Interval (28º to 55º):

CON: conditional raster=“DEM_Slope”, where value is greater than 28 AND value is less than 55, true raster=“DEM_Slope” -> Con_Slope28to55

Slope Change (>10º):

DIF: “DEM_Slope”, "Con_Slope28to55" -> Diff_SlopeMax_ConSlope28to55
CON: conditional raster=“Diff_SlopeMax_ConSlope2855", WHERE value is greater than 10, true raster="Diff_SlopeMax_ConSlope2855" -> Con_DiffSlopeMaxCondSlope28to55
RECLASSIFY: I don't know how to reclassify to prep layer for Raster to Poly featuring only slope interval 28<slope<55 combined with slope change >10º -> Reclassify2_SlopeMaxConSlope28to55
RASTER TO POLYGON: "Reclassify2_SlopeMaxConSlope28to55" -> RastToPoly_SlopeIntervalSlopeChange

Large Surface Areas (>625 m2)

CALCULATE FIELD: area
SELECTION: areas>625 m2

Close to Glaciers:

EUCLIDIAN DISTANCE: "Glaciers_Raster" -> EuclidDist_Glaciers
RECLASSIFY: "EuclidDist_Glaciers" with 2 classes=[0-200 (5); 200-50282.359375 (1)] -> Reclassify2_EuclidDistGlaciers
RASTER TO POLYGON: "Reclassify2_EuclidDistGlaciers" -> RastToPoly_ReclassEuclidDistGlaciers

Finalize:

CLIP: "RastToPoly_SlopeIntervalSlopeChange", "RastToPoly_ReclassEuclidDistGlaciers"

Is this workflow OK? What mistakes am I making? Should I try a RWO approach instead? THANKS!

Re: Avalanche Hazard Mapping without vegetation

DanPatterson — Fri, 11 Mar 2022 10:08:11 GMT

Results? Do they make sense? or did you get any errors?

During the process were the cell sizes the same? snap raster? extent?

Environment parameters will have an effect on processes and output

Re: Avalanche Hazard Mapping without vegetation

SMangum — Tue, 15 Mar 2022 03:52:25 GMT

Hi Dan,

I'm thinking about trying a different approach. See the following post in ArcGIS Pro Questions:

1153652

Re: Avalanche Hazard Mapping without vegetation

DanPatterson — Tue, 15 Mar 2022 10:15:00 GMT

profile or plan curvature?

Curvature (Spatial Analyst)—ArcGIS Pro | Documentation

Re: Avalanche Hazard Mapping without vegetation

SMangum — Tue, 15 Mar 2022 17:51:14 GMT

Huh! I think that's exactly what I need. You're a genius!

If I understand correctly, the input raster would be my DEM_Slope raster. Or am I confused here?

And what constitutes noisy data and how do I know if I have it? High resolution?

My cell size is 10mX10m. Is that high resolution? And if so, should I try the SURFACE PARAMETERS tool instead?

Re: Avalanche Hazard Mapping without vegetation

DanPatterson — Tue, 15 Mar 2022 19:21:01 GMT

see you other thread Calculating slope change - Esri Community