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Mapping walks

Monday 15 February 2021

As I mentioned last week in Pandemic walks, part of the fun of the long walks I’ve taken with Nat is mapping them out. The tooling is a hodge-podge of discovered things along the way, but it works for me.

Planning

Each walk is kept in a GPX file. I can get a picture of where we’ve been on previous walks by looking at them as a collection. Dérive is a simple elegant site that will map a set of GPX files dropped onto it. It’s open-source, and they even implemented a feature request I made.

To plan the walks, I originally used gmap-pedometer.com, but now I use On The Go Map. Both will create a route between two points automatically. On The Go has a big clean layout, and I can tweak the plan by dragging new points in the middle of the route as needed. Gmap-pedometer has more options for map sources, but I found On The Go was better at knowing where I could walk, and making correct routes automatically.

It helps to have a good planning tool because I want to get the right distance, not too short and not too long. I also want to include new streets we haven’t visited before.

I use Google Street View to take a look at spots I’m uncertain about. Is that a street or driveway? Can you get from the end of that street into the park next to it?

Walking

Before heading out, I print the map, on paper! It’s easier than fiddling with the phone, and I can draw on it if we go off-plan or if I want to make a note of something we saw along the way.

I use my phone to figure out where I am when I am uncertain, and I have a link to a large map of all of our previous walks if I want to consider an ad-hoc addition.

There might be apps that can track my walk automatically. I’ve used some in the past that captured an approximation, so I would rather map them myself.

Recording

Back home after the walk, I can use the route from On The Go Map, or re-plot it if needed. On The Go gives me the GPX file to add to my collection, and gives me the distance walked for my stats spreadsheet.

When I want to know more about the history of the place we’ve been, I use Mapjunction. It’s a great dual-view of two maps at once, of your choice. For example, you can look at the current streets and the same region 100 years ago to understand how things have changed.

To produce the animated GIF in the last post, I cobbled together a program using a bunch of tools I didn’t fully understand! The result is gpxmapper. It uses Fiona to read the GPX files, Shapely to compute and plot the geometries, and Cartopy to draw the maps. This was definitely a copy-paste patchwork, so don’t take it as the work of an expert. It works, but I can’t promise it does it the best way.

I got some inspiration and headstart from a recent Boston Python presentation: On Python and Positioning: An Introduction to Working with Geospatial Data in Python with GeoPandas by Heather Kusmierz.

The program writes out a pile of PNG files, then uses ImageMagick and Gifsicle to wrangle them into a good animated GIF. A large static version of the total walks is posted online for me to refer to in the field if needed.

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Some of this might surprise you as low-tech. For a software engineer, I tend toward low-tech. And as I mentioned in the last post, this whole walking endeavor has given me a much deeper understanding of the neighborhoods around me. Working with the maps to plan and record the walks is part of that process, so I’m not looking to make it more automated.

That said, if you have suggestions, I’m interested to learn!

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