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A map of Yosemite
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Four Mile Trail (Yosemite Valley to Glacier Point) #55

Open gophersnake opened 10 years ago

gophersnake commented 10 years ago
  1. There's actually a short spur trail to Union Point. NPS signage gives its length as 200 feet. That junction is an important landmark for what follows.
  2. "4" hasn't been the correct length of the trail for many years. NPS signage isn't entirely clear and consistent on this point but the distance from Southside Drive to the Union Point junction is given as 3.0 miles and the distance from the UPJ to Glacier Point (or the Glacier Point end of the trail, which is not exactly the same thing) as 1.6 miles.
  3. The map shows the first (lowest) series of switchbacks more or less correctly; there are 6. There should be 35 in the next series, including the more gradual "pseudo-switchback" correctly shown at the top, almost directly north of Union Point. A few of the latter switchbacks are in fact so close together that they probably wouldn't show up at the scale of the map but quite a few more switchbacks should be shown. More info starting here: http://yosemitenews.info/forum/read.php?3,66049,66149#msg-66149 Continuing: the 5 switchbacks in the series just below Union Point are shown more or less correctly but the first (lowest) one is actually much more acute than the map shows. Most of the 13 switchbacks above Union Point are shown correctly but the topmost one is in fact more acute than the map shows. The final portion of the trail, from the topmost switchback to Glacier Point, appears more or less correct but I haven't been on it as much, nor collected any data on it.
closedcontour commented 10 years ago
  1. Will add.
  2. I'm generating my mileages based on the path data, not NPS signage, literature, or anything else. I'm open to having overrides of the path data when something is considered more accurate. Also, if we correct the path as you discuss in (3) it will likely become longer.
  3. Great info, I'd love to get this correct. Do you have any software where you can draw the correct route? Perhaps in www.openstreetmaps.org?
gophersnake commented 10 years ago

I still need to do some tinkering with my plot of the Four Mile Trail. Would two weeks be soon enough?

What I'm thinking of doing is encoding my plot in a format similar to GPS plots, then letting you deal with getting the data onto the map as if it were from a real GPS.

There's one conspicuous geographical feature that I've never seen mapped -- the two white-looking, rock-and-gravel-filled chutes that the Four Mile Trail first avoids, then eventually crosses. They show up in satellite views but never on maps that I know of. Here's a view (a bit on the hazy side, I'm afraid) from Columbia Rock. The trail zigzags up that green band from the bottom right to the top left:

dsc20167

Here's a "closer" view:

dsc20169

closedcontour commented 10 years ago

Anytime you want to give me the data I can get it in there. No hurry on my part.

As far as those rock streaks... it sounds like I should do the work to get the landcover data into an editable form. This will take some time on my part but once I have it in place I can start to make changes like this.