Not all saved layers are visible in the UI

achiacchierini's Avatar


17 Apr, 2019 09:20 PM

I recently created a series of DEM Shading layers to be applied to any map
based on the backcountry avalance forecast (see attached). Ideally, you'd
have a printable map of the terrain with color coded zones reflecting the
relative risk of aspect and elevation. These maps could be created by a
user each day or posted on a website for the major BC skiing zones like CO,
the Sierras, the Wasatch, etc.

I created 120 layers. For each of 8 aspects--N, NE, E, SE, S, SW, W, NW
(defined by degrees)--there are 5 avvy ratings (low, moderate, considerable, high, and extreme), and 3 elevations (1: >11,500' [above
treeline]; 2: 11,250' to 11,500 [around treeline]; 3: <11,250' [below
treeline], which I roughly based on the Berthoud Pass area of Colorado).
The idea was to toggle/overlay the appropriate layer based on the forecast.
For example, if the forecast rates N and E aspects above treeline as
considerable and as moderate around treeline, I could toggle the
appropriate layers (my naming convention): N1 cons, E1 cons, N2 mod, E2
mod. This forecast is unrealistic but it uses the layers I can access. see

My main problem is that the active layers drop down in the UI can't fit all 120 of the saved custom layers and there is no slider to scroll down to
the ones that won't fit on the screen. The layers are saved to my account,
but I don't know how to access and activate the ones that are now visible
in the UI.

Do you have a solution for this?

Also, I'd like to add some graphic overlay for the type of danger
associated with each layer. For example, if the "wind slab" danger is
considerable and the persistent slab layer moderate, I'd like to
distinguish those types of danger and, at least, represent the highest
danger in a given aspect and elevation.

Any thoughts on that would be great as well.

I understand that my descriptions may not be entirely clear. Please, if you
have questions about what I am trying to do or suggestions please reach out
for clarification.

Lastly, I am not entirely happy with the colors I chose. I was trying to
make subtle distinctions between different aspect while maintaining a theme
for each level of risk. IOW, low-risk is a slightly different shade of blue
for each aspect at each of the 3 elevations (8 aspects and 3 elevations).

Any thoughts on that would be appreciated as well.

  1. Support Staff 1 Posted by matt on 23 Apr, 2019 09:24 PM

    matt's Avatar

    I'm not trying to tell you how to plan your trips, but I do want to note that when developing the slope angle shading layer, I experimented with a danger rose style approach to specifying colors, and explicitly decided against doing so as I felt it was misleadingly specific.

    Wind slabs are a good example of this - consider an E-W ridge that branches off of a N-S ridge, with wind loading on East aspects. The North slope of the E-W ridge is going to be subject to wind loading from the larger N-S ridge, despite not being truly East-facing and therefore not being captured in the DEM shading.

    When you add a custom DEM shading layer, there's a dropdown to set it as a base layer rather than a transparent overlay, which means it shows in the layer dropdown rather than as a checkbox. This would help you get around the size limit.

    You can also stack multiple shading statements together in the same layer. So instead of creating 100 different layers and manually toggling them in the UI, you can do Add New Layer -> DEM Shading, and pick several slope/aspect/elevation ranges custom to that day.

  2. 2 Posted by achiacchierini on 23 Apr, 2019 10:41 PM

    achiacchierini's Avatar

    I hope this is above the reply line in the right way.

    Good insight. I agree, the shading doesn't supplant putting all the
    pieces together especially with regard to cornices and wind slabs from
    adjacent aspects that compound risk or bleed into lower rated aspects.

    What I've found is that pointing out the forecast on specific aspects
    is good broad brush to start with when figuring out where I want to go
    and how I want to get there.

    I figured out that the base layer feature woudl have been a better
    application as well. Further, all the saved DEM shading layers do
    appear in the load from drop down, just not in any recognizable order.
    It's not perfect but once the order gets sort of memorized it's not
    that big of a deal. I was just a little panicky after manually
    inputting 120 different aspect/elevation/risk coloring codes which all
    appeared available until I started anew with a fresh map.

    Another way in which the aspect based color shading is helpful is
    timing the corn cycle. Given the state-wide high pressure last Friday
    and the exteremely safe consolidated snowpack, I used the sun surveyor
    app (another great tool, especially for figuring out when the shadows
    will start to cool the flatirons for trail running on summer evenings)
    to get a sense of the angle of incidence throughout the day and then I
    figured I'd head up Mines Peak and wrap around from NW to W to SW
    until the snow started to get soft mid morning. It worked to
    perfection and we laid down tracks in the Vortex on perfect corn. Did
    I need maps and apps? Probably not, and I could have just followed
    that strategy in my head. Still, it did help our timing and gave me
    some data to bolster the argument I was making to my aerospace
    engineer girlfriend that we were on track, but needed to keep a decent
    pace on the up.

    Anyway, I am fascinated by maps and am using a series of different
    configurations/looks created in Caltopo for the area around Byers Peak
    to decorate the walls of our condo in Fraser, almost Warhol style.

    I can't say enough good things about your site and have been
    evangilizing to everyone I know about it.

    Not to eat up any more of your time, but do you have any tips for
    creating a heat map of my logged trail runs over the course of a year
    in certain zones? I've started to dabble but between the quirky
    exporting of GPX and KML on Suunto's site and the loading and graphics
    on Caltopo, I have kind of put it on hold for the moment.

    Thanks for getting back to me.


  3. Support Staff 3 Posted by matt on 26 Apr, 2019 03:01 AM

    matt's Avatar

    No suggestion on building a heat map. You can load a bunch of tracks into CalTopo and set them to have a wide line with with only 30% opacity or so, so that overlapping lines will appear darker, but I wouldn't really call that a heat map.

    The sun exposure layer (as a checkbox in the layer menu, or with aspect-based intensity shading as a custom layer via the "add layer" option) uses ray tracing rather than just looking at the point aspect, and sounds like it would help as well.

  4. System closed this discussion on 02 Oct, 2019 04:25 PM.

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