High Resolution Elevation Data
CalTopo first launched the slope angle shading layer 7 years ago. Since then it has become a mainstay tool for backcountry trip planning. Today we’re updating the layer to incorporate high-resolution LIDAR data from the USGS’s 3DEP program. Where available (see coverage map), this provides significantly higher resolution, even allowing you to identify trails from relief shading. As additional coverage becomes available we will add it to this layer.
While the LIDAR data is very high resolution, it should still not be relied on as a definitive source of truth. Beyond possible errors or accuracy issues with the dataset or our processing of it, the surface angle on top of a snowpack may not match the bare-ground angle underneath. Carefully assess and evaluate any terrain that you are traveling in, and confirm your observations instead of relying solely on maps.
This update is now live on the web! It will be released soon on iOS and Android. Offering online access for free, and offline downloads with a CalTopo subscription. The significant increase in resolution means the offline downloads are larger in size than previous elevation data. Be cautious downloading using mobile data and storing on your phone, storage may go quickly.
As with previous expansions of the slope angle shading layer to Canada and Alaska, the high resolution dataset is not available to third party apps that license CalTopo’s pre-rendered layers like Gaia GPS and Backcountry Navigator. You can only access the layer via CalTopo’s website and app; we encourage you to download the new app to use this layer in the field.
Please, when we are looking at a map on CalTopo, how can we tell if the slope angle shading we see for a specific area is based on LIDAR data / is “high-resolution”, or if it is based on the “old” lower resolution data? Thanks!
Here is an interactive coverage map: https://caltopo.com/l/CM87
Is the CalTopo higher resolution elevation and slope angle coverage map at https://caltopo.com/l/CM87 current and up to date as of 8/7/2020 ?
What’s the current plan for expansion of coverage?
Thanks!
The layer is up to date. We’re currently rendering world-wide elevation. 3DEP made a large update to their coverage at the end of July. We’re planning on picking up that update and rendering it before ski season begins (by October/November)
Following up re the Oct/Nov update to the high-res elevation estimates and slope angle estimates. Has this been implemented? asking, because I want to let folks know once it is implemented and tell people about 1 more reason to use CalTopo and purchase a CalTopo subscription.
What a fantastic resource!! Similar to the earlier question, is the map included in this post available interactively online anywhere? The 3DEP coverage maps I am seeing have different regions shaded and are similarly static images.
Here you go! Took us a day to get it worked up, this is an interactive layer showing coverage. https://caltopo.com/l/CM87
Fantastic, Ben. Thanks so much! One additional clarifying question…which layers (besides slope shading) incorporate the new hi-res data? Thinking about some of the other derivative tools like contours, the real-time cursor elevation, DEM Shading, sun intensity, etc. Thanks for all the hard work of the CalTopo team!
Contours are not updated (which is why they look a little strange still, however elevation shading including custom layers, and hillshade/terrain shading layers do incorporate the new data. Therefore if you add Normal/Enhanced shading to a map layer where available high resolution elevation data will be displayed.
Awesome! Looks like 3DEP is targeting full coverage of the US by 2023. Curious if you looked at local resources to fill in some of the holes sooner? E.g. in Washington state, there’s quite a bit of data available here: https://lidarportal.dnr.wa.gov/#46.91650:-121.46484:7
At this point we incorporated the 1m, 1/9th arc second, and the standard 10m NED data from USGS, including smoothing and managing between which data to use when multiple were available. There’s a little bit of reluctance to get too in the weeds with local LIDAR data since, 1, many of the local entities are or will be incorporated in the 3DEP data set, and 2. there is potential conflict checking/data currency issues when starting to incorporate lots of data sets in that manner. We do intend to update the data model with some regularity to continue to incorporate additional high res data as it becomes available.
do you have a sense when the broader sierra might see the lidar treatment?
Unfortunately no. It’s a USGS program, I know they are hoping to have the entire US covered by 2023 but I don’t know what their priorities or timeframe is. We will update periodically as new data becomes available.
got it. do you happen to know if they plan to turn this information into a new generation of topo map? on quick glance it looks like an amazing resource, though the discrepancy between existing quads and the lidar shading is pretty odd to look at!
Caltopo: Please, I’m curious to learn about the precision of the older slope angle estimates and elevation estimates, and about the precision of the new LIDAR based slope angle estimates and elevation estimates. Please, what can you tell us about the precision of these estimates? Thanks!
Purposes/Context:
– To better understand the advantages of using slope angle estimates and elevation estimates based on the new LIDAR data;
– To better understand the imprecision of both the old and new slope angle estimates and elevation estimates, so as to help people understand that even the new data is not 100% precise, and should be used with caveats and caution and intelligence, and confirmed with boots on the ground and boots on the snow terrain scouting and observations, ideally on “lower-risk” days in terms of avalanche risks, weather, etc.
Hi Ben, When I draw a line and extract a CSV file, is the elevation data from the 1 meter LIDAR in areas with coverage?
Please Please can you finish LIDAR for the Adirondack Park in New York State! It seems to cut off the most remote section of the Adirondacks
Please Finish the LIDAR for the Adirondacks in NY state. It seems to cut off the most remote sections of the Park. I may have posted this already but Don’t seem to see it on this thread. Thanks
Insightful post, I’m glad I came here.
Glad to hear you found it informative!