Geo-spatial PDF’s, CalTopo, and pre-winter training!

My head is still spinning from some of the info I’ve been able to pick up this past weekend. It all started Saturday morning with Marc Chauvin’s, of Chauvin Guides, informative presentation on creating geo-spatial PDF’s that can be uploaded into a smartphone GPS app to supplement your outdoor navigation capabilities. This somewhat esoteric topic is right up my alley and while the content could seem a bit heavy at times Marc’s energetic & well timed presentation made it easy to stay fully engaged from one concept to the next.

Marc's presentation

Marc walks us through creating Geo-spatial PDF’s and importing them into GPS enable smartphone apps

I won’t go though the step by step process here but if you are interested I’ll make some suggestions. First, get to know A colleague pointed me to this website a year ago and it took me awhile to give it a solid look. This seminar gave me the kick in the pants I needed to start playing around with it and I am simply amazed at what the free version of this website offers. It is hands down the best online mapping resource for outdoor recreationalists. The potential use & application of this program is so large I can only scratch the surface here, but to wet your appetite the first thing I did was create some routes down the popular ski routes in Tuckerman Ravine using satellite imagery, which, with the click of one button, could easily be imposed over USGS Topographic info:

Tuckerman Ravine Ski Routes

Tuckerman Ravine Ski Routes

This a more accurate way of measuring important drainage scale info than estimating off a topographic map, and the website easily displays information about each run, for example, Hillman’s Highway is .42 miles long and drops from 5179′ to 3923′, and total vert. of 1256′. You can also get “Terrain Statistics” for each route you created, for example, Right Gully:

Screen shot 2015-12-06 at 10.52.42 PM

It felt steeper than 36 degrees! This is excellent information to have when managing avalanche terrain choices!

What really got me excited was seeing the layering potential of the website. Being able to layer crowd based info (like unofficial mountain bike trails) on top of verified info (like USGS maps) is amazing, especially when you can make these maps GPS enabled on your Smartphone! To top it all off though you can have the software shade specific slopes based on info you specify.

For example, if your local avalanche bulletin suggests to avoid slopes NE-NW aspect above 7000 feet that are steeper than 35 degrees due to a Persistent Slab problem? You can actually enter this slope criteria and these areas will be shaded! It really is impressive. A short video of the developer that references this ability right at the end:

Marc has made an excellent video highlighting this feature. Check it out here:

Once you have a decent understanding of CalTopo you can use the website to print or export custom PDF maps. The fun doesn’t stop here though! The next step is to download the Avenza PDF Maps app. This free app lets you import your newly created PDF maps and make them “geo-spatial”? What does that mean? It means you can use these maps with the GPS chip of your smart phone to show your location. Marc has been getting into the mountain bike scene lately and there are many mountain bike trails that you won’t find on regular USGS or even hiking maps. With this two-shot combo you can upload any map, “sync” it with a base map, and voila, you can navigate and see your location on the hybrid creation!

For practice in the class we imported a Green Hills Preserve map that showed some popular mountain bike trails over your standard USPS map. After “geo-marking” two reference points on the map it scaled and aligned perfectly.

Green Hills Map

Green Hills Map

If I was still at the Grand Summit Hotel when I took this screenshot my location would have been pinpointed on this map with a little blue dot.

Finally this technology is easily shareable. The CalTopo website will create unique URLs of your creations that you can easily share with climbing & hiking partners. I’m planning on having a master map for our back-country skiing trips on Washington that guides can edit as they get more accurate GPS positions on first aid caches, drop points, bailout options, etc.

I planned to talk about our pre-winter EMS Schools training but I’ve run out of time so that will come later. Also, there’s been some healthy debate about whether one should trust their phone GPS over a dedicated unit. I’m writing a detailed post looking at some recent research and arguments for and against using your phone GPS for wilderness navigation. Please stay tuned for that!

See you in the mountains,


Tuckerman Ravine Ski Routes

Tuckerman Ravine Ski Routes



About David Lottmann

David grew up skiing in the Whites and started climbing at a summer camp just north of Mt. Washington when he was 16. Those first couple of years solidified climbing as a lifetime passion. From 1996-2000 he served in the USMC, and spent the better part of those years traveling the globe (18 countries). After returning to civilian life he moved to North Conway to focus on climbing and was hired in 2004 as a Rock and Ice Instructor. Since then Dave has taken numerous AMGA courses, most recently attaining a Single Pitch Instructor. He has completed a Level 3 AIARE avalanche course, is a Level 2 Course Leader, holds a valid Wilderness First Responder and is a member of Mountain Rescue Service. When David isn't out guiding he enjoys mountain biking, kayaking, hiking, backcountry skiing, trying to cook something new once a week and sampling new micro-brews. He lives in Conway, NH with his wife Michelle, son Alex, and daughter Madalena.
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2 Responses to Geo-spatial PDF’s, CalTopo, and pre-winter training!

  1. David (Dave) Tewksbury says:


    Thanks for the post on CalTopo, neat site I was not familiar with.

    Happy Holidays!



  2. Pingback: Should you use a Smartphone for Wilderness Navigation? | North East Alpine Start

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