/ gis • my projects • survey data / Comments Off on Atlas of Legal Needs Surveys
This summer I had the pleasure of working with CORE GIS to build a web map for the World Justice Project. One of their ongoing programs is to aggregate surveys of unmet justice needs from all over the world, and we made them an overview map to present the data:
The map and filters are automatically populated from a file that WJP maintains, to give them a straightforward way to update data without having to engage a consultant each time. The underlying data is more impressive than anything we built, though: the screenshot really is highlighting a 129,000 person face-to-face survey conducted the year before COVID.
/ getting on the map • gis • my projects • osm • transport / Comments Off on Gaining elevation
A/B Street is both a game and a very powerful tool that allows you to download a detailed street map of an area and test out changes to the configuration of roads:
It uses OpenStreetMap as a data source. OSM has impressively rich data on things like the number of lanes a street has, where bike lanes and turn restrictions go, and so on, but one thing it lacks is detailed elevation data. The developers noticed that it was suggesting absurd routes for cyclists in Seattle, including routes that no-one who’s actually tried cycling would ever repeat because of the hills involved. So they brought me in to figure out how to add elevation data.
I wrote a simple Python tool that reads in paths as plain lists of coordinates, and writes out statistics for each one: the start and elevations, and cumulative elevation gain and loss along each path. A/B Street incorporates this into a data load by exporting each road segment as a series of points every metre along the way, getting as fine-grained a picture of a route’s hilliness as the source data allows.
By default, elevation_lookups uses data from the Shuttle Radar Topography Mission, because that source provides fairly high quality data for most of the world’s land. I learned about SRTM while making this tool, and I’m still sort of star-struck that we have a global dataset like this, freely available to anyone who has a use for it. But it is also relatively low resolution, so I built in the ability to override the data source with higher resolution sources where known. It comes preconfigured with examples of both raster (LIDAR source) and vector (contour source) datasets for the Seattle area.
This is an open-source project. I hope it can be useful for other applications, and I have more ideas for it then I have time to implement. I’d love contributions from anyone this appeals to, and have some suggested starting points (not all requiring programming skills!).
/ gis • my projects • outdoors / Comments Off on Staying relevant when the ground shifts
Before the pandemic, I was working on a major update for Washington Hometown’s recreation mapping work. They’ve long been a major provider of outdoor recreation data, but wanted to put more of that data into public-facing maps that they host. They partnered with TOTAGO for mobile maps, and I built a map generator for their desktop maps so that they would be able to quickly publish new thematic maps by just updating some configuration files rather than having to write code each time.
This flexibility turned out to be more important than any of us had anticipated, because before the project wrapped up the pandemic hit. In the first months of Washington State’s lockdown, a lot of public land was either entirely closed to the public or had very limited services. Suddenly being able to publish a spring hiking map just didn’t seem relevant or even appropriate any more. But WHT’s speciality is keeping data current as things change, and they applied the same mindset to the map themes themselves. At the height of public confusion about where to find COVID tests, sanitiser supplies, and so on, they released a “crisis” map with that information updated daily.
As things calmed down, they quickly pivoted away from the crisis map (quickly enough that I didn’t even get a screenshot of the working map!), and started focusing on the ever-changing list of which public lands were open, closed, or somewhere in between. Now that we all know that outdoor activities are relatively safe, there are far fewer closures, but still enough that it’s valuable to have someone keeping track.
I was impressed with my client’s ability to keep this project relevant when I was afraid that the pandemic would sink it. And in the end it’s been a great validation of the map generator itself, which has helped them to stay agile.
/ gis • housing • land use • my projects • seattle / Comments Off on Fitting more housing into the city
Seattle is suffering from a deep housing affordability crisis, with more and more people being priced out of living there. At the same time, it’s been deeply resistant to changes in zoning that would allow enough new housing to be built. One of the examples of this is that it has a program called “Encouraging Backyard Cottages”, and has gone through at least two rounds of legal reforms to support that, but figuring out whether one can be built on any given lot still involves going through a long checklist about the exact dimensions of the site and intricacies of zoning.
In theory, DADUs (Detached Accessory Dwelling Units, the much less appealing legal term for “backyard cottages”) allow a lot of small, affordable housing to be added to single-family zoned neighbourhoods and spread out enough to not feel like a radical change in the streetscape. In practice, the complicatedness of the process adds enough of a barrier that relatively few have been built so far. Hatchback Cottages has a plan to solve this with a set of ready-to-build designs and a package of support to help people through the process.
Even with their expertise, assessing a site under the arcane rules is a time consuming process. But computers are good at applying lots of rules and calculating all the measurements, so Hatchback contracted me to run a GIS analysis assessing every residential lot in Seattle for suitability.
Fortunately for us, Seattle and King County publish very comprehensive and regularly updated open data about zoning and development, so I had a lot to work with. The analysis takes into account existing building footprints, lot characteristics and potential complicating factors like steep slopes and landslide hazard areas. It will never be a complete replacement for a knowledgeable human looking at the site, but by ruling out all the sites that definitely won’t work it saves my client a lot of time. Now the experts can solely focus on sites that have a relatively good chance of working out.
I grew up in Britain. I rarely feel like moving back, but there are some genuinely wonderful things about the place. One of them is the incredibly comprehensive network of public rights of way, especially in rural areas. The basic principle is that any path that’s been in common use, stays in common use, even if the “path” is nothing more than a customary route across the middle of a field. Landowners are not allowed to obstruct public access on foot, and in turn walkers are supposed to respect farmland by sticking tightly to the established path, keeping dogs under control, and so on. And because most of the British Isles have been relatively densely populated for a long time, there are customary routes all over the place.
Although there are sometimes conflicts, the system mostly works. It’s helped along by strong social norms, and a healthy dose of fierce and nerdy advocacy. Landowners aren’t generally obliged to do trail maintenance, so sometimes it’s done by local governments, and more often by volunteers. Farmers do tend to maintain stiles to allow access from one field to another without letting livestock out, and in the more populated parts of the country there’s usually someone providing stream crossings.
/ climate • gis • seattle / Comments Off on Pacific Northwest climate trends
The University of Washington Climate Impacts Group has built a new visualization tool for the state climatologist, which makes it easier than before to explore the whole climate record for Washington and some data for neighboring US states. The data itself is nothing new, but being able to explore it can help to get a handle on what’s going on. I rather arbitrarily picked my life to date as the range to compare, and got the sobering result that every single monitoring station has registered an increase in temperature since I was born; most statistically significant.
Of course, there’s no scientific basis for picking that particular range, but I wasn’t cherry-picking either (I’d have picked 1985-2015 if that were my goal). I just wanted dates that felt personally meaningful, and even as someone who considers myself relatively well-informed about climate change the sheer scale of the trend was breathtaking.
/ climate • coral atlas • gis • my projects / Comments Off on Allen Coral Atlas
As a child, I adored the National Geographic magazines. I collected them for long enough to fill a bookshelf, and I think it’s fair to say that they had a pretty big influence on how I’ve ended up making a living. So it was particularly satisfying to see a project I’ve been involved with since the summer get a writeup in National Geographic:
It’s a wonderfully ambitious project—using imagery that wasn’t available 5 years ago—and terrifyingly urgent. Coral reefs are particularly sensitive to the impacts of climate change and ocean acidification, and massively important as both habitat and shoreline protection. We have very little time to left to figure out ways to make them more resilient, or lose a major source of protein and watch storms do more and more damage as the reefs’ protection is lost.
My role is to integrate the processed data we get from two different research groups: one infers depth from the satellite imagery, and the other classifies areas of reef by types of sea floor and what’s growing on them. I write automation that turns the depth data into false-colour imagery, and prepares everything to be displayed in the web map. Here’s a snapshot of that depth imagery:
So far we just have a single snapshot in time of 6 reefs, but the real challenge will be scaling that to all the reefs in the world, updated regularly. You can explore it yourself and read about the methods and partnership at http://allencoralatlas.org/ .
Because it’s a limited preview so far and most areas aren’t covered yet, panning and zooming around the globe isn’t very satisfying. I recommend clicking on the place names in the “Mapped Areas” list to see where we actually have data. And for a first look I prefer to turn all of the data layers off, zoom to a location, and then turn them back on one at a time starting from the bottom of the list.
I am often a bit skeptical—perhaps more than you might expect from a GIS consultant—of the value of displaying information on a map rather than a chart or a table. Sometimes clients ask for maps simply because they look good, without thinking about whether geography is a useful dimension for the questions we want to answer. These two were interesting cases because geography is relevant, but not for the most obvious reasons, and this influenced their design:
The internal tool is for lobbyists to show to state politicians, so the design is very focussed on zooming to individual districts and showing how they compare to others. In the big picture that’s not exactly the ideal way for politicians to make choices, but we all know that they do it, so it’s realistic for an advocacy group to appeal to this bias.
The public map is a way of showing just how big a public funding advantage charter schools have over public schools. The message would have been lost in a chart or table, because the same unlevel playing field benefits rural school districts (which don’t generally have charter schools nearby) over urban ones. Putting the map together helps us to compare like with like. I don’t know anywhere near enough about Texas education politics to know if either bias is deliberate, but assigning blame is outside the scope of a map anyway. It’s enough that it shows the effect of a policy.
As someone who uses Census statistics regularly in my work, I am concerned that if this is allowed to go through it will leave us unable to rely on the 2020 count as the accurate snapshot we depend on it being. As a citizen and resident of this country, I am afraid that what we’re seeing is a deliberate attempt to skew future elections and federal government resource allocations by systematically undercounting the population of areas with more immigrants.