Premise

Compute a series of weighted-average soil texture fractions (sand, silt, clay), for every component, of every map unit in Yolo County. These values will be further weighted by the spatial distribution of each map unit.

STATSGO KML thumbnail

SSURGO KML Thumbnail

A short update to a previous post on the visualization of NCSS/USDA soil survey data in Google Earth. The use of the NetworkLink construct, combined with the spatial indexing present in PostGIS, allows for very rapid lookup and presentation of this massive database. Scale-dependant switching between the detailed (SSURGO) and generalized (STATSGO) databases is done through simple area calculation in PostGIS.

Here is the link to the KMZ file. Here is a link to our conventional viewer application, based on Ka-Map / Mapserver, using the same PostGIS back-end (previous post on this). This PLSS KML file is very useful along-side soil survey information.

 
Feedback is always welcome!

Most of the work is being done in the Lewis-1 watershed.

content here

• 5 meter interval sampling of contours
• 5 meter interval sampling of terrain skeleton
• [5 10 15 20 25 30 40 50 60] meter thinning (snapping) radius

 
Compute SD of elevation on 50x50 meter grid

 
Site Description:

• Description on the US Forest Service site

 
Some possible approaches

• r.angle.sh (see image below and attached script)
  

First Pass: Terrain Skeleton

• Track Log Data (white flow lines are from original 10 meter USGS DEM)