Slope Angle Estimates - over what distance and in what direction(s) from a point is slope angle estimated?

Tom's Avatar

Tom

10 Mar, 2020 08:59 PM

Note: I'm not asking for any trade secrets or proprietary information, but for general knowledge useful for a person who uses CalTopo slope angle estimates.

- As I understand slope angle, 2 points are needed to estimate a slope angle. Is this correct?

- As I understand slope angle, 2 points ("the run"), and the elevation difference between the 2 points ("the rise"), are needed to estimate slope angle. Is this correct?

- For any specific geographic coordinate/location/waypoint, how does CalTopo determine the 2 points used to estimate slope angle?

Thank you!

  1. Support Staff 1 Posted by rmarcucci on 10 Mar, 2020 11:13 PM

    rmarcucci's Avatar

    Tom,

    You have the basic idea, the reality is just WAY more complicated than that. We get our data from publicly available datasets from the USGS. Here's a recent blog post post regarding some new high resolution data: http://caltopo.com/about/2019/12/20/high-resolution-elevation-data/

    With that raw data, we create a model, which we use for contour lines as well as slope angle shading. CalTopo has created a proprietary algorithm to analyze points in that model in relation to adjacent points, and create the slope angle shading you see on the map.

    I hope that gives you a basic understanding of how the whole thing works.

    All the best,
    Rom

  2. rmarcucci closed this discussion on 10 Mar, 2020 11:13 PM.

  3. Tom re-opened this discussion on 11 Mar, 2020 06:35 AM

  4. 2 Posted by Tom on 11 Mar, 2020 06:35 AM

    Tom's Avatar

    Thanks!

  5. rmarcucci closed this discussion on 11 Mar, 2020 04:46 PM.

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