Caltopo Adds Weekly High Res Sat Images

[TurboHike]

I like the new feature on CalTopo! It allows one to see at a glance where there is snow and then decide about bringing microspikes or other traction gear. Yes it doesn't show snow depth, but we already have that information from USDA and other sources.

[c9h13no3]

I'm former SAR, and rescue people on a regular basis while out and about doing other things. Realists clash with rabid optimists frequently.

And I suppose when the car was invented, all EMT's bemoaned the increase in car accidents they had to respond to.

Cheer up emo kid.

[maverick]

Stick to the subject matter please, thank you.

[SSSdave]

Back from my backpack, now have a chance to look at that dramatic game changing feature more closely. As a long time user of all manner of maps, especially USGS topographic and geological maps, I've used complementing Google Earth 3-D extensively since it came out to evaluate landscapes for photographic features like rock color and vegetation states. Although NASA MODIS has been a valuable addition, this new feature is of an order of magnitude significant increase in value. On what I've already initially seen it is enough that I would consider the caltopo account option. Many of my trips, especially now in retirement when I can pull the trigger on trips at short notice, depend on narrow windows of conditions and even a weekly update has great value nailing timing. Just like with any satellite images clouds are always going to be an image to image limitation and that would be more so about regions where clouds are more common.

( Note our forum attachment image add tool seems to significantly blur original images thus my text is barely readable. Next time will increase the font size. And oddly it also doubles the size of images that makes that worse.)

SFSJ-HR7219b.jpg

Immediately see more interesting uses than just looking at snow. Looking at large rivers, one can actually see sections with whiter hues indicating more whitewater versus dominant blue stream areas where water is absorbing blue skylight. I was just on the South Fork of the San Joaquin River and can readily see the difference in places where rapids were most dramatic. The width of the stream color also indicates stream size with creeks less than river size invisible. Whiter granite is distinguishable from darker metamorphic rock. An issue with Google Earth has always been the large variability from natural colors due to image processing although in recent years that has greatly improved. This Caltopo image appears nicely color accurate though is understandably rendered a bit dark, however that can be manipulated with Photoshop. I can distinguish the lighter greens of aspen from those of darker conifer forests. Note I enhanced the above Snipping Tool capture in Photoshop that better brings out the color differences.

DorothyL_HR7219b.jpg

The above shows Dorothy Lake surface ice breakup in Convict Creek canyon while slightly lower elevation Mildred Lake is already snow free. That could be a boon to those fishermen that want to hit such waters when fish are most hungry. One can easily distinguish the granite southwest of Dorothy versus the rusty orange metamorphic rock just north. No more hiking XX miles climbing XXXX feet just to find that lunker lake is still frozen. Giantbrookie will like this.

I pulled up the same Convict Creek region but using the 1 year ago image and saw in excellent resolution smoke in that area from a fire northwest in the lower San Joaquin River canyon. Thus in late season will be able to use such information to assess smoke issues. Looking at Rim Fire areas of Kibbie Ridge one can easily see what burned and what did not.

AVPR-HR7219-3mb.jpg

This next image above shows Antelope Valley California Poppy Reserve region 3 months back thus April 2. I've Photoshop enhance the web image. The orange hued poppies strongly stand out as well as expanses of yellow hued goldfields that dominated Fairmont Butte. Greener areas to frame upper right are a mix of fresh green grasses and flowers. With weekly updates, people will be able to nail wildflower landscape work during peak conditions better than I've ever been able to.

[Wandering Daisy]

After lookin at some of the images, it appears that snow cover under a thick tree canopy is under-estimated because the snow is not "seen" from the satellite. In all the early trips I have done this year the most snow in the 8000-8500 foot range has been deepest in forests. Although not full coverage, the remaining snow is quite deep- 3-4 feet, at 50%-75% coverage.

[Dwwd]

Recently I also learned about Sentinel Hub website. I particularly like the sentinel hub playground page(shown by SirBC above) over Caltopo for looking at snow and lake "ice-out" images. In Sentinel Hub there is a wider range of effect options to illuminate features of interest. In the effect tab you can modify gain(brightness) and gamma to enhance the outlines of frozen lakes. Which allows one to address the perennial question, "When can they be fished with no ice"? In addition, by choosing different wavelength bands is it possible to discern snow in trees in false color vegetation images. Some user practice is required. Given the high resolution images in Sentinel, it would be very nice if folks would post the view/size of a snow field on a "Mtn pass of interest" in Sentinel and then show the real photos to develop some correlation references over time in years. Of course, one can watch for PCT class of 2019 or Mt. Whitney forum real photos and generate your own personal comparison.

Also Sentinel Hub is free, unlike the possible future of the Caltopo interface.