matt on 23 Apr, 2019 09:24 PM
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.
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.
matt on 26 Apr, 2019 03:01 AM
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.