Thursday, April 2, 2015

Improved and Printable Elevation Profiles

Elevation profiles are one of the few remaining gaps people have noticed when comparing CalTopo to desktop software.  No more.

There are now two profile modes - the existing interactive one that uses Google elevation data, and a full-page version that builds on the terrain statistics dialog with CalTopo sourced elevation data.  You can get to the new profiles using the terrain statistics menu option, or clicking the expand link at the top right of the interactive profile dialog:


The expanded version is a full-page dialog:


One of the most obvious differences is axes in place of rise/run data:


There's also a heatmap below the profile showing slope angle, land cover and tree cover along the route:

Below that is the previously existing terrain stats content (lines only - terrain stats along a polygon's perimeter, to match the profile, would be meaningless or misleading).  A more subtle addition is that nearby markers are automatically placed along the profile:


Using bulk ops, you can also plot multiple lines on the same axes:

Absolute plots the lines' actual elevations, while relative shows how each line changes from its starting elevation.  Below are 3 routes plotted against each other in absolute mode (top) and relative (bottom).



PDF versions of any profile are available using the print link at the top right of the dialog.


Note that because the interactive profile uses Google data and the expanded profile uses CalTopo data, gross gain and loss numbers may be slightly different.  Like terrain stats, expanded elevation profiles will only work within the continental US.

6 comments:

  1. Thanks, this is really nice! Love the idea to show the profile together with the heatmap of the slope angle!

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  2. I think another nice feature (if possible) would be to implement Naismith's rule for calculating an estimate of "time to hike".

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  3. Your maps are new to me and I've become fascinated with watching the California wildfires. Could you please explain why sometimes the map updates with new info on one active fire but not on another -- is it interference by the smoke layer? Thank you.

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    1. Fire perimeters are reported to a federal coordination center by the individual fire's management team, and the timing is up to that team.

      Thermal hotspots are processed from the MODIS satellites' IR band. I'm not well versed on exactly what's going on behind the scenes, but heavy cloud cover - not so much smoke - can obscure the satellite's view. Also, although active fires will get lots of overlapping circles, there's some processing to prevent already-hot areas from showing up over and over again. So even with a clear view, you may not see new hotspots within the fire perimeter, even if those areas are still "hot".

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  4. hi how are you
    I like to know why the utm grid or latitude\longitude grid could not be seen more lower than the equator line. for example i was just trying to make some maps from brazil with the layer opencyclemap, and the utm grid doesn't appear.
    Could you please help me?

    Thank you a lot!

    Sincerely

    Juan M Diaz Soto

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