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new source for online topo maps


mattyj

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If you'll excuse the self-promotion from a new member (I'm down in California and lurk before hitting the Cascades to play on glaciers, but that's it), I've recently spent a lot of time, energy and sadly money assembling a nationwide (lower 48) topo layer from the USGS's new high-resolution scans. This is a third alternative to Terraserver and MyTopo, and although each one has pros and cons, I think it kicks Terraserver's butt and holds its own against MyTopo - without their annoying watermarks.

 

To check it out, go to http://caltopo.com/map.html. Click the + in the top right corner to add relief shading. If you click the print icon at the top, you can print the map out at any size you want, including poster sizes if you have access to a printer that large. Chrome will do borderless prints, Firefox adds a border, and IE stumbles a little.

 

If you log in at http://caltopo.com/ you can also draw on the map, share it, embed it in a TR and transfer GPS tracks - here's an example. The homepage also has some links that demonstrate what you can do with the different map layers, like shaded relief aerial with contour lines and mixing the aerial and topo layers. The USFS and historical map layers are currently CA-only, but will be expanded to the lower 48 sometime next week, as well as getting scans of the USGS's 1x2 maps for when you're zoomed out.

 

I originally started this to give my local SAR team a better mapping option - being able to do things like printing an aerial image with a NAD27 UTM grid can be a big plus at times. If anyone is on a team and interested, check out http://sarsoft.org and http://code.google.com/p/sarsoft. I can get you all the map layers for your state (except aerial, but we can work on that) on a drive so that you can run the whole thing in the field without an internet connection. California takes up about 250GB, including 100GB for aerial imagery.

 

Hope you like it. Feel free to send me comments, good or bad.

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I like it. Thanks for sharing it -we all appreciate it.

 

Check this crazy thing out. Been using Acme mapper for a few years and it's awesome. Spend 5 min with it. Look at the satellite picture (upper R hand corner), mark the cliff (lower R hand corner, switch to topo and look at the approach. Cope paste co-ordinates and send them to your buddies. Crazy fun.

 

 

http://mapper.acme.com/

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The way web maps work is that you get a fixed number of zoom levels, with the scale doubling each time you zoom in. In order to print accurately, you set the viewer dimensions to match your paper size, and then you pan/zoom to the map you want. So yes, each time you zoom, the print area will double/halve in each dimension. The mercator projection that Google Maps uses also doesn't have a consistent scale - it grows as you travel further away from the equator. The upshot is that while you can print maps with a scale and UTM grid for judging distances, you can't print a map at fixed 1:24,000 scale that will work with plastic UTM overlay tools or exactly match a USGS 7.5' paper map.

 

I'm familiar with the Acme mapper and it's a great tool, but there's a couple areas I thought I could improve on. First, MyTopo recently changed its licensing, which forced Acme and a bunch of similar sites to drop them, leaving only Terraserver - and their scan quality isn't very good. Second, the ability to blend multiple layers - variable shaded relief being the most obvious example. Third, by adding the ability to draw lines and use custom symbols as markers, allowing people to create something closer to a "real" map than a set of waypoints.

 

I did email the Acme guy to see if he'd be interested in including my map tiles so you might see them on there at some point, although I need to work out how much it would bump my hosting costs.

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Is it possible to use CalTopo as a WMS server for topo software? If so, what would the request look like?

 

Sorry. I rendered everything into 256 pixel web mercator squares and stuck it on Amazon. The advantage to this is that I don't need to pay to keep a big server running, one of the disadvantages is no WMS interface.

 

Terraserver stuck everything in a database and warps/serves it on the fly, and despite having Microsoft's resources behind them, they're still slow at times. I wouldn't have a chance.

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Thanks all. I just switched on the new nationwide USFS layer. It doesn't cover all the national forests and most of the maps don't have green vegetation shading, but they do a better job showing roads, trails and private/public property boundaries than the USGS quads.

 

Very helpful when you're trying to navigate a series of cryptically numbered logging roads.

 

Stinkydog - working on center crosshairs.

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I was bummed when ACME lost access to the MyTopo maps. I switched to http://www.mappingsupport.com/p/gmap4.php which has fantastic maps but is kind of a pain in the ass to print from. I had to take screen shots and then manipulate them into powerpoint to get the right view, but also while trying to keep the proper aspect ratio.

 

This on the other hand prints in seconds. Thanks!

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gotta give you a huge congratulations for producing such an awesome map-software! this is leaps and bounds above everything else I've used. I'm spending more time browsing on it than prior map programs, as a map fanatic who can spend hours looking at them this just works great. esp like the measuring feature and how easy it all works together. you did a super job!

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Is anyone else having trouble printing a USGS 7.5' overlayed with the shaded relief and having the shaded relief show up on the entire page? (it shows up in my in Firefox just fine)

I'm getting it to print only on the upper left hand section of the screen, the rest just prints the 7.5' map.

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LukeShy -

 

Please PM me the specs for you computer (OS, Firefox version, etc), and confirm that you're using the print icon in the upper right to adjust the page size. Also send me the map ID (if it's a map you've created) or the URL string, and the page size you're using.

 

It works fine on the browsers I've been able to test, including an up-to-date copy of FF on Mac and Windows, but browser printing is always a little problematic; this is why Google generates a static image for printed maps. I'll see what I can do.

- Matt

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I've added a slope analysis layer that allows you to shade slopes by angle and aspect. It's a good high-level visualization of potential avalanche starting zones that can assist with safe route planning, but it's important to remember that it's also just a tool, it should be one of many in your toolkit, and is in no way a substitute for good decision making based on conditions you observe on the ground. Some known limitations are listed here: http://caltopo.blogspot.com/2012/02/avalanche-slope-analysis.html

 

As an example, here's Shasta shaded by slope angle:

http://caltopo.com/map.html#ll=41.4,-122.2&z=14&b=t&n=0.25&o=r&a=slp_s-11111111

shasta1.jpg

 

And here's Shasta with the S-E aspects shaded orange:

http://caltopo.com/map.html#ll=41.4,-122.2&z=14&b=t&n=0.25&o=r&a=slp_a-11333111

shasta2.jpg

 

You can click the + in the top right corner to switch between shading by aspect and angle, and also to enter danger-rose-style colors when shading by aspect. I'm still trying to sort out some server performance issues, so the shading may take a while to load.

 

This is all highly experimental, and I welcome any feedback. In particular, I had to take guesses at what slope cutoffs to use and how to actually do the shading. This info is on the bottom right of the screen, but since it's subtle:

 

Shading by aspect: slopes between 28 and 59 degrees are shaded, with 35-45 having dots on top to differentiate them.

 

Shading by angle:

20-27: green

28-34: yellow

35-45: red

46+: blue

 

If you'd rather use his tool, there's a good chance ryanb will be pulling this into hillmap.com, although I'm not sure exactly what form it will take.

Edited by mattyj
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