Slope Angle Overlays for the 48 states and bits of AK

[SirCasio]

Very slick...planning on an update anytime soon?

[ryan b]

Skipping work to ski today so this has to be quick but just added a bunch of stuff (drag and drop gpx import, new "caltopo" map layer, other stuff) and more is on the way as I have time. Color gradient slope stuff as discussed hera and extending to canada/europe are high on the list.

[Buke]

Really sweet site.

As for a non skiing use, I'm a structural engineer and I just used the profile feature to calculate wind speed up effects for a building site.

[::: :::]

ryan, just wanted to say this tool rocks!

[Dromond]

I always wanted a tool like this. Thanks!

[whippersnapper]

Hmm, worked for the West but on Stowe it has a mathematical error...either a coefficient is wrong or it's gradient vs. degrees, not sure. >50deg input shows where slope is actually around >25deg., very roughly.

[ryan b]

Can you let me know the lat and long of the area you are looking at and the settings you are using so I can look into it? Or email me a screen shot through the link on the site?

I use the same code for the east and west but it may be something weird with the underling data service from the USGS being off by a ratio for that area or having some artifacts there.

Or you could be using too small a resolution and picking up a fake drop off between the discrete elevation values in the data...at high resolutions it will think contour lines are cliffs with flat spots in between.

I'm working on putting up my own elevation data service which will hopefully solve a lot of these issues and let me extend coverage outside the us and do higher res analysis...I want to be able to highlight small pockets of steepness in otherwise safe areas.

[whippersnapper]

Can you let me know the lat and long of the area you are looking at and the settings you are using so I can look into it? Or email me a screen shot through the link on the site?

I use the same code for the east and west but it may be something weird with the underling data service from the USGS being off by a ratio for that area or having some artifacts there.

Or you could be using too small a resolution and picking up a fake drop off between the discrete elevation values in the data...at high resolutions it will think contour lines are cliffs with flat spots in between.

I'm working on putting up my own elevation data service which will hopefully solve a lot of these issues and let me extend coverage outside the us and do higher res analysis...I want to be able to highlight small pockets of steepness in otherwise safe areas.

Ahh, well sorry I'm not good at finding lat/long info or screenshots, but Jay Peak a bit farther north works fine, and I kept resolutions at 40m for both, but checked 80m in case and got what you would expect at 80m vs 40m in both places. I know that Google Earth lost some rights to data right at Mt. Mansfield (NNW of Stowe VT), so I think it's a local data anomaly, not a coding problem on your end.

EDIT, ah, look at 44'31'52 N
72'48'51 W, which is right at the chin of Mt. Mansfield on Google Earth (look *without* your plugin but straight from GE), there is a big square hole about 8 miles across. It's been there for months...who stole that real estate! A topo will appear if you toggle USGS but that ain't the same...WTF?

Hey thanks for a cool program!

[eshed]

Bump because I recently discovered hillmap and I find it bad-ass. Thanks!

[ak_powder_monkey]

Whats the resolution of the DEM you used? I'm guess its that 10m space shuttle lidar?

[Peruvian]

I have loved using the hillmap.com site for several years, but the slope angle overlay no longer works for me. Is anyone else having this issue? Maybe I fucked up my settings somehow.

[John_B]

Hillmap hasnt seen anything for development in the past 3 or 4 years. I'm not sure if slope angle is sourced from Caltopo too but Caltopo has definently been cutting back on data layers they provide to other sites.

I get by well with Caltopo now but I sure wish they had the side to side window like Hillmap. That is a great feature.

[ryan b]

I got a real job and had a couple of kids so haven't had time to work on hillmap beyond basic keep the lights on stuff. (I wrote it years ago if that isn't clear).

It does look like the caltopo slope layers are no longer loading. Not sure if that is them shutting down access or they just moved them. Similar thing has happened with many of the external services that drove much of site either disappearing or no longer being free which has caused a slow rot in the available features.

If any software engineering/gis folks wanted to take over maintenance/management we should talk. I've thought about open sourcing stuff but due to changes in how they charge for the google maps api the site would probably need a significant rewrite to get off of that before doing much more with it.

Matt at caltopo has also done an amazing job and gone beyond the basic mash up I did to producing his own novel layers.

[Peruvian]

Thanks for the reply. I appreciate it with or without the overlays.

[GoldMember]

^^ I have used hillmap several times for various endeavors but never realized 'The Dude' was on TGR. First, thanks for having built that program, it's very useful and cool. Yes, miss the profile/topo. I don't know if that's retrievable somehow but is a great feature for plotting a path and for knowing slope angles.

Kudos to you for a very useful app.

[John_B]

Ha. Add me to the list of folks that are thankful Ryan!