Monday, September 8, 2014

End to End: Closed Contour Yosemite Maps

A few years ago, I ran across Dan Cervelli's excellent Closed Contour map of the Sierra.  At the time I was just getting started with CalTopo and learning my way around GIS, and Closed Contour really opened my eyes to the cool stuff you can do with Mapnik.  I had no idea it was so simple to take some shapefile data, add a few rendering commands, and then boom, beautiful looking maps.  At least, the tools are that simple - obviously there's still a lot of talent and hard work involved in producing the final product.

The original Closed Contour map was built on a projection and tiling system incompatible with Google Maps, so integration into the universe of sites and apps using that as a de-facto standard was not possible.  Dan has a new Yosemite map built around this standard, and I thought it would make a great end-to-end demo of some things CalTopo can do with "web mercator" tile sets.

Step 1: Add a Custom Layer

The more maps, the better - CalTopo is built around the idea of combining different map layers into a single coherent picture.  Unfortunately, I have to balance supplying layers of regional or special interest against providing a reasonably compact, easy to navigate UI.  The middle ground I've settled on is to make it easy to add custom layers from a tile URL or WMS address.  You can also choose from a preset list of useful layers, which Closed Contour has now joined:

Closed Contour now appears in the layer dropdown alongside the standard CalTopo layers

and provides a snazzy backdrop for some route planning, complete with trail mileages

You can also skip these steps and just visit to take a look.

Step 2: Make a PDF

I've already covered printing multipage PDF map packs and loading Geospatial PDFs onto your smartphone, so lets just jump ahead to the results:

The Half Dome hike fits onto a single 1:24k scale 8.5x11 print.  Compare Closed Contour, above, to the USGS 7.5' topo below:

I can also load this into Avenza PDF Maps to plot my location and record tracks when out in the field:

Step 3: GPS and Google Earth

Both Google Earth and newer Garmin GPSs know how to read layers exported from CalTopo as KMZ files.  So lets go make one:

This gives me a better GPS map of Yosemite than money can buy:


And some pretty nice 3-D visualizations:

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