measure slope/plan trips on google maps

So this winter i got frustrated with the available online mapping tools and wrote a google maps mash up to help me plan backcountry trips. It gives you:

* Side by side, coordinated topo and satellite views.
* Basic slope estimates at a point.
* Overland distance and elevation gain/loss for trips (change the mode to path).
* Point forecast at weather.gov

It is still somewhat buggy but I have been finding it very useful and I just got around to posting somewhere publicly accessible (google app engine for the geeks). Check it out and let me know if you have any feedback or feature requests...I'm doing this in my spare time with zero budget but I'll try and make improvements as I can:

www.hillmap.com/

(let me know if this too spamy for TAY ... i figured it is at least on topic)

this is pretty cool - although it would be very useful to be able to draw a line and get the average slope on the line instead of at a point

Could you make it look like the images on this page:

avalanchesafety.blogspot.com/2010/10/union-creek.html

Very slick.

Any idea how accurate google maps is for estimating slope? It looks like 40' intervals.

Average Slope:
I just uploaded an update to do average slope of the last link when you put it in path mode but you may have to clear your browser catch to get it to work. This is the slope of the line that connects the two points so it doesn't consider any local roll overs or steepness transverse to the direction of the line etc.

Overlays:
I'd love to do slope overlays like that but google limits the the amount of calls you can make to their elevation service to the point i can't even do max slope along the path at a reasonable resolution. I may try and get by hands on some elevation data some other way so I can do things like that but no promisses.

Resolution:
Google doesn't publish resolution but claims that their elevation data is the best that they can get their hands on for any given area but that resolution varies. They do the interpolation and give you their estimate of elevation for the points you request.

I estimate the maximum slope by requesting points in a circle around the center and seeing which one has the biggest slope...you can adjust the radius of this circle in the settings panel to see what effect this has if you want.

So its an estimate based on estimates and I wouldn't trust it in the place of actually measuring. I have been comparing it to what I see with my compass inclinometer and it does good on open slopes but it can radically underestimate the slope of vertical cliffs (climbing not skiing terrain) and be thrown off by the walls in narrow couloirs.

Neato Ryan, that's very convenient and useful.

Thanks,

I'm getting some reports of things not working for some people from friends and would appreciate it if anyone for whom the site doesn't work can let me know what it does and what browser version and os they are using so I can try to fix it....I've only tested it on my computer.

Ryan

Cool stuff Ryan! Not spammy at all... "of interest to the ski community", after all...

very nice tool. I've seen a few mapping tools show up, this is the first one I have seen with a slope angle tool.

is there a way to share the route as seen via email... for collaborating upcoming trips with touring partners?

is there a way to switch backgrounds to a USGS map like from mytopo.com?

Yeah, great stuff.  Haven't run it yet, but sounds handy - should be a time saver -  I've been using GE and the path/elevation on a manual level for some time to get a sense of line angles.  Have noticed that the 'path' feature follows the 'nap of the earth' (as it should, I guess), so somehow there is an algorithm at work.. , and so at least gives a visual on where the convexities, etc, are at.

a bit of a drift, but I've had fun recording 'flights' of routes (using the 'record a tour' button).  Besides using sticky pins to identify points of interest, I identify ski lines of interest using the 'Path' feature and saving them, then, having tilted the perspective (ie not from directly overhead), and finding a suitable bearing and range to view from, will record a tour of the area (once 'record' is on, you can get the screen panning with well timed click and drag).  That tour is saved in GE as a .kmz file which can be mailed as a link when you want to share the route with others - great visual tool.

very nice tool. I've seen a few mapping tools show up, this is the first one I have seen with a slope angle tool.

is there a way to share the route as seen via email... for collaborating upcoming trips with touring partners?

is there a way to switch backgrounds to a USGS map like from mytopo.com?

I'm working on both of these things, you have to apply to get the mytopo.com api and i think my application got lost in the mail when I tried a while ago but I think i should be able to get it now that I have an actual site.

Route sharing will take a bit of back end work but should be easy enough thanks the the flexibility of python/appengine. I am considering doing it like this and I'd love to know what people think:
* Save a route to your account (app engine lets you log in with your google or other open id account) but keep it private.
* Create a link like www.hillmap.com/route/ALNFLDFJH8nlZ (with or with out logging in) such that anyone with the link can see your route.

When you say collaborate would you want multiple people to be able to make changes to the same map...ie shared ownership or would it be sufficient to simply make a copy for each collaborator and make a new link each time you made some changes?

I could also add import/export for text based formats pretty easily if people want it.

I'm also planing on adding a feature to plot an elevation graph of your trip and can add any other plots or statistics for trips people want to that (should I graph the slope of travel as well as elevation for example?).

I've also been thinking about cookie monsters suggestion more and I think something like that should be doable for at least parts of North America using usgs etc data. I'm imagining an option to switch the right map to a heatmap of slope. The coding should be easy enough (I do a lot of large data analysis in my day job) but serving it will be a bit more intensive and will probably knock me over the free appengine hosting quotas if a lot of people start using it a lot so I might replace the google adds with some backcountry.com affiliate links or something to try and pay for this sort of thing but I'll try to keep it as unintrusive as possible. Google can't seem to figure out the site has nothing to do with the chevy avalanche anyways...

That is a lot of rambling and more then I will get done in the near future but I'll try to implement the things that seem most popular first so let me know.

And thanks for all the great feedback, I'm really happy people are finding it useful.

When you say collaborate would you want multiple people to be able to make changes to the same map...ie shared ownership or would it be sufficient to simply make a copy for each collaborator and make a new link each time you made some changes?

for collaboration I was thinking something like. I create a route with your browser mapping tool. The work is saved automatically in the URL. I simply copy/paste the URL into an email. My touring partner(s) can then see exactly what I drew... and continue editing. Then they can re-send the new revised URL (map). And so on back and forth until we map out our plan. (It would be great to easily print that too)

All the features you cold put into the browser would be great. the slope angle tool, Notes, waypoints, anything would be useful too, icons... (campsite, ski slope, trailhead).

Route sharing will take a bit of back end work but should be easy enough thanks the the flexibility of python/appengine.  I am considering doing it like this and I'd love to know what people think:
* Save a route to your account (app engine lets you log in with your google or other open id account) but keep it private.
* Create a link like www.hillmap.com/route/ALNFLDFJH8nlZ (with or with out logging in) such that anyone with the link can see your route.

My 2cents on creating an account. In the early days of sharing photos online, photo sites would require recipients to create a "quick" sign up in order to view the photos you shared a link with.... and nobody would take the time. Consider, many emails between friends are read during working hours, it needs to be quick and easy.

Cool, I got basic path sharing setup, hit the share/save link on the lower left to generate a link like this one:

www.hillmap.com/m/agtzbG9wZW1hcHBlcnIPCxIIU2F2ZWRNYXAY6QcM

I'm going to try to clean up the ui a bit next and test it to make sure it isn't breaking on other browsers etc, after that maybe add notes and better maps,  improve the path editing, plots, gps import export and the slope heatmap (all as i have time of course).

Edit: found a bug that limits the number of points save will work for, will fix it tonight.

I sprained my ankle at the climbing gym last night and am now couch bound and this has given me a some time to work on this. I added a lot of features:

You can chart elevation and slope of travel for the whole trip (hit profile on the lower left).
You can move the pins while profiling and it will update the charts.
You can click on a blue line to add a pin in the middle of the route if you need to refine the route.
You can make notes, they show up as white pins.
The saving bug is fixed.

Check it out:

www.hillmap.com/m/agtzbG9wZW1hcHBlcnIPCxIIU2F2ZWRNYXAYox8M

Dude, that's just great.
Does everything just right.

The only slight improvement I can think of would be to be able to zoom in a bit closer to the map so when you 'point' click a narrow couloir you know that you're getting the slope angle for the middle, not the steeper sidewalls.

Brilliant & simple interface. Love it

Thanks Jake!

The couloir thing is kind of tricky if they are narrow enough to be near the resolution of the source data which I think must be 10-30 m NED data for most of the US because the elevations i use are interpolated by google and the walls may throw off by their smoothing...I think routing a path down the couloir and looking at the slope of that using the profile tool gives the best estimate of what is going on. That said, I am working on getting some better topo map tiles (mytopo.com and Microsoft Research's USGS scans) which will let you zoom in further and visually inspect things and I may eventually do my own interpolation of the NED data.

Great tool and thanks for sharing.

Thanks Scott.

More features I've added:
* USGS Topos maps and aerial images from Microsoft Research Maps Webservices
* Printable display of USGS maps from the above (still working on the ui for this but if you play with it
you can get some good results).
* Switchable dual map views.
* An about/how to dialog.

Excellent development.

Using the USGS Topo maps it's possible to zoom right in. Thus it's possible to get a totally accurate slope angle measurement (I know I'm sad...).
I also like the toggle between split & single screens as I don't really use split screens.
You've lost the distance measurement on the profile-path x axis which was helpful.

Excellent stuff. I'd be really happy to help test it. Feel free to PM me.
Jake

I really like the development of this tool. Thanks for putting in the work, I'll definitely put this to use in trip planning.

One more idea... it is possible to toggle the tools/footnotes etc. to either minimize or temporarily hide them in order to maximize map size while working with the map? This would give maximum workspace for working with, and maybe printing.

Thanks guys.

Jake, axis labels are there in chrome still I hadn't realized I broke it in firefox...I'll fix it soon.

Koda, I'll see what i can do about a fill window mode but you should give the print dialog a try for printing...it lets you generate a higher resolution map (by making a bigger webpage) which should give you better prints if you tweak your printer settings to scale it to fit your paper...you may have to play with various settings.

Topos for Canada from NRCan will hopefully be up soon, still waiting on mytopo.com other stuff will take longer.

Feel free to PM me with any issues or bugs or suggestions, I don't have official testers or anything...

Sorry to dredge up an old thread but I am stoked. After much hacking I managed to implement cookiemonster's suggestion of slope angle overlays in a way I am starting to be happy with. It lets you highlight areas steeper then any specified slope angle and it works for the entire lower 48 states, hawaii and parts of alasks.

To try it:

Go to hillmap.com

Navigate to your area of interest.

Click on "data and analysis" at the top of your screen.

Click on "hillmap slope analysis"

Click on "Analyze on Screen Area"

The results are calculated (by javascript in your browser using data loaded from usgs webservices...it may take a few seconds) for the onscreen area only but they stay on the map as you pan and zoom so you can do the analysis for the whole area of interest and then zoom in.

There is a lot of artifacting (pixelation and contour lines) in the resulting analysis due to the resolution of the underlying USGS data service so I wouldn't trust it as my only source of information but I have found it to be be very useful for getting the lay of the land...I hope some of you find it useful too.

Awesome!

The results are fantastic!

Thanks Ryan.

Being that its still dry (cold and windy this week) in the Sierra's I've been doing more map skiing than I'd like and recently looked up this thread to find hillmap again. I'm sure others forgot or didn't know about it.

One glitch I found: When I zoom into the area analyzed, it freezes the contour map (but highlighted areas zoom in and out still). Any idea why, browser maybe?

Really cool feature though.

Way cool. Thank you!

Thanks for the compliments and bug reports.

If the slope angle overlays don't work for you try it in Google Chrome. I will work on fixing it for other browsers but that is the one I use for development. It won't work for for IE <=8 due to the lack of support for canvas.

very cool tool, ryanb!
i'm testing all my favorite spots
thanks very much!

This tool keeps getting better and better.
The convenience is key.
I've done a lot of similar analysis in GIS, but this interface and ease of use is paramount.
Thanks!

Hey All,

Mattj and of caltopo has developed (and shared) a great new slope overlay layer for the US as well as higher quality scans of the USGS and FS maps. I've wired these into hillmap (+ drag and drop GPX import and overlaying map layers) and you can now do things like this:

www.hillmap.com/m/ag1zfmhpbGxtYXAtaGRychALEghTYXZlZE1hcBia8REM

Which I have been finding useful with touchy recent snow conditions. (satalite+.5 opacity fs map + 1 opacity caltop slope overlay. Tour was yesterday, recommend heading further west on the way back to tronsen at the end to avoid dense trees.)