search

WikiWatershed / model-my-watershed

The web application front end for Model My Watershed.
https://modelmywatershed.org
Apache License 2.0
57 stars 31 forks source link

MapShed: Calculate LS #1277

Closed rajadain closed 8 years ago

rajadain commented 8 years ago

LS can be calculated using NLCD, Slope, and Stream Density. A finer method may involve using Flow Accumulation, but unfortunately we don't have a Flow Accumulation raster at 30m resolution.

Use DRB streams if the polygon is wholly contained within the DRB, else use NHD streams.

See if this geoprocessing can be combined with any in #1272 or #1274 to improve performance.

rajadain commented 8 years ago

To calculate Average Slope over an entire area, use:

{
  "input": {
    "polygon": [],
    "targetRaster": "us-percent-slope-30m-epsg5070",
    "rasterCRS": "ConusAlbers",
    "polygonCRS": "LatLng",
    "operationType": "RasterAverage",
    "zoom": 0
  }
}
jtarricone commented 8 years ago

Won't the average slope be calculated as part of #1289 ?

rajadain commented 8 years ago

You're right, it should.

jtarricone commented 8 years ago

Coolio, I'm at a decent stopping point until that gets merged. The LS factor calculation should be in place, so any additional work after #1289 should be minimal, barring math errors of course.

rajadain commented 8 years ago

This should now be unblocked

rajadain commented 8 years ago

It'd be great to get a PR for this up soon so I can rebase #1305 over it