Urban footprints: some building outline data sources

This is an informational post about where to find building outline data, which I've used a lot in previous GIS projects. It might also be of interest to architects, engineers and anyone interested in urban studies and planning more generally. I like using this kind of data to explore cities as it gives us a good idea of the layout of the urban fabric, as in the example below (New Orleans). The links mainly refer to data from the US, Canada and Great Britain but other parts of the world are covered to various extents by OpenStreetMap.

New Orleans

Let's start big, with OSM... Steve Bernard has produced an excellent video which explains how you can get OpenStreetMap data directly into QGIS very simply - he uses Madrid in the example. The accuracy and coverage varies a great deal across the world, so you need to bear this in mind when downloading and using it - but on the whole it is a fantastic resource. The example below shows Mogadishu, where the coverage is incomplete for buildings but pretty good for the road network. 

© OpenStreetMap contributors

Another useful OSM-related resource with decent global city coverage is CAD Mapper, where you can download areas up to 1km square for free. However, I'm focusing on open data today so will not go into detail on this. The best OSM download source is I think GEOFABRIK (German for 'geo factory), a German GIS consultancy who extract and process OSM data and then make it available for free online. It's really nicely structured and easy to find what you're looking for. Here's the download page for New Zealand, for example - followed by the contents, where you can see the building data on top of a current OSM base map. At time of writing, the zipped shp folder for the whole of New Zealand was 146MB.

The New Zealand GEOFABRIK download page (20 July 2015)

Auckland, NZ - very good building coverage here

The OSM sources are great, since the licence is very generous and you can use the data for just about anything, so long as it's properly cited. However, many towns, cities and counties across the world also provide building footprint or outline data (the terminology varies from place to place) so I've put together a list below of ones I know about. Some of them (e.g. Detroit, NYC) cover land parcels or tax lots so are slightly different but in the main it's just building outlines. I've included visuals for some of the datasets, so you can get an idea of what they look like.

New York City - from the BYTES of the BIG APPLE website you can download the MapPLUTO dataset, for all 5 Boroughs in New York City. Tax lot level rather than building outlines, but it's an extremely rich dataset with loads of useful land use planning variables in it, including 'year built' and number of floors. A little sample of the data are shown below, for the area around Central Park.

A little sample of the data (using Qgis2threejs)

Chicago - the building footprints layer is avaiable in two versions online, one of which says it is deprecated but I've heard from the Chicago GIS team that this isn't the case. It's just that due to limited staff the dataset is only edited when necessary. Also contains a 'year built' and height variable.

San Francisco - another really good city buildings dataset, from SF OpenData. Also lots of useful variables in this dataset, including height. I really like this one.

Dallas - you'll probably get a disclaimer box in a pop-up when you go to download this. I've linked to the general GIS page and the file you want is called Structures (Building Footprints) in the Planimetric Data section - it's about 81MB to download and the unzipped file is well over 100MB.

Atlanta - again, I've linked to the GIS page, this time from the City of Atlanta and you need to download the 'Impervious Buildings' layer. If you're looking to map the sprawl of Atlanta, this won't work as it covers the City area only. Still, a very useful dataset.

Denver - excellent open data from Denver. This dataset covers all permanent structures and buildings for a 152 square mile area of the City and County of Denver. Available in a number of different formats.

Seattle - this dataset was created in 2009 by Pictometry International Corp but is now in the public domain. It is available via the City of Seattle's data website.

Los Angeles - this is a fantastic dataset for the County (not just the City) of Los Angeles, which is the most populous county in the United States (just over 10 million). Made available via the LA County GIS Data Portal. It is a little hefty (581MB) so be careful! In the example below I show all the buildings in LA County but the City of Los Angeles in dark shading, just to emphasise its crazy shape.

Boston - this was created in 2012 and is available via the City of Boston. Contains a number of different fields, including base elevation of the structures, the elevation of the highest point above sea level and fields on building type.

Detroit - like New York, not strictly a buildings outline file but instead a property lot level dataset. Very impressive dataset produced by Data Driven Detroit's Motor City Mapping project. I've used this data a lot in talks and teaching as it's a really good example of its type.

Now some links to further datasets which I know of but haven't used that much...

Washington DC - link is to the download page, but direct link to zip is here (559MB unzipped)

Baltimore - the top link on this page

Philadelphia - via OpenDataPhilly

Massachusetts - buildings for a wide range of towns and cities in the state

Boulder - this is from Boulder County, Colorado. Available in a number of different file formats.

Bloomington, Indiana - one of many smaller cities with excellent geodata

New Orleans - an excellent dataset, not just because of the unusual shape of the city!

Toronto - don't be confused by the '3D Massing' terminology here. Scroll down to the 'Data download' section

Vancouver - doesn't cover the whole city and they were digitised in 1999 but still a useful dataset.

Waterloo - this is from the Region of Waterloo and was up to date as of January 2014.

Hobart, Tasmania - an nice example of building data from Hobart in Australia. Contains a 'year constructed' variable.

Wellington, NZ - can't overlook New Zealand! I think you need to register to download this but it's Creative Commons 3 so still open. 

The list wouldn't be complete without mentioning OS OpenData for Great Britain, provided by Ordnance Survey. A new dataset with detailed buildings became available in March (the OS Open Map - Local) dataset. The building data is a very small part of this collection but one I find very interesting. I've patched together a few cities here to get the ball rolling but you can download your own. There's also a 'tile finder' to help you identify which OS tile you need to cover your area of interest. 

This could save you some time 

I think this just about covers it. Get in touch if you have any other great data sources for building outlines.

How many people live in Tokyo?

Back in August 2014 when I was preparing some material for teaching students how to query data in a GIS, I devised a very simple example where they had to select all the countries in the world with a lower population than the Tokyo Metropolitan Area (or Greater Tokyo Area, as it's sometimes called). I did this just as an example but since I found the results quite interesting, I quickly turned it into a map and posted it on Twitter, complete with 'Toyko' typo in the subheading. It was really just a quick example of how to query data in a GIS but it also highlighted the massive population of the Tokyo metropolitan area. You can find the full size, original image here. I was prompted to write this blog because the map was reposted on the Canadian Twitter feed @AsapSCIENCE a few days ago and since then my inbox has been a bit busy.

Now, back to the original question of how many people live in 'Tokyo'. Well, when I say 'Tokyo' in the map, I'm referring to the wider metropolitan area, which in 2014 the United Nations World Urbanization Prospects said has a total population of 37,833,000, far beyond the next largest urban agglomeration, Delhi, at 24,953,000. By way of comparison, using the urban agglomeration population (rather than a city's administrative boundaries), Toronto had 5.9 million, London had 10.2 million and Beijing had 19.5 million. Clearly, these definitions include other urban places that are not Tokyo (e.g. Yokohama) but they are recognized as being part of a fairly coherent metropolitan area. 

So, in the map, I'm using a figure of 'approx 36 million' as I say but in reality the UN figure is a bit higher. If we want to narrow the definition down to just the inner urban area then obviously the figure reduces significantly. I'm not usually one to cite Wikipedia, but in this case it's a good place to go to learn about the various definitions of the Greater Tokyo Area/Kantō region. If you don't want to click, here's a summary of some Tokyo populations...

• Former city area (23 'special wards') - 8.95 million people
• Tokyo Metropolis - 13.05 million
• Tokyo Metropolitan Employment Area - 31.70 million
• National Capital Region - 43.47 million

If we take the metropolitan definition used by the United Nations, then Tokyo does indeed have more people than Canada, at 35.5 million (2014 Statistics Canada estimate) and far more than Australia at 23.7 million (see their population clock). The Tokyo metropolitan population is roughly the same as the whole of California, which currently stands at about 38 million.

Link to chart

This was all just a little bit of map trivia and whilst it seems to have annoyed some people who live in a red country, the point was just to demonstrate the simple analytical power of GIS in addition to the size of Tokyo (to make it more interesting). The data I used are from Natural Earth if you want to have a look yourself and the software I used is a free GIS called QGIS, which is really good. Some other random facts about what happened to my original tweet...

• It was tweeted by Guardian Cities and then retweeted 309 times and favourited 107 times.
• It was tweeted by AsapSCIENCE on 22 January 2015 and since then retweeted 96 times and favourited 110 times.
• Akihabara News wrote an entire article about the map, and even spelled my name correctly - that hardly ever happens.
• Tokyo Desu also did a piece on it - and added another map too.
• What does it all look like on the ground? This photo (below) from ATBREAK gives you some idea.

Tokyo metropolitan area

Journal Rankings from Australia

A lot has been written (e.g. see this) about the RAE, so this is not the focus of this post. Instead, this post is about journal rankings. The link here is that the eqivalent exercise in Australia (Excellence in Research for Australia, or ERA) has produced a ranked list of journals to be used in assessing academic outputs. Clearly, this is contentious and controversial and it has heated up exchanges in e-mail lists worldwide. It has also been written about in the mainstream press.

First, though, where can we find these rankings? Click here to find them, and click on the next link to download the Excel spreadsheet with all the data.

In many nations, academics are assessed on the basis of their research outputs. Here in the UK, this was previously done using the Research Assessment Exercise and will next be done via the Research Excellence Framework, in 2012.

Journals are ranked on a four-point scale: A*, A, B and C. Clearly, this is not good news for C-ranked journals or, in fact, most B-ranked journals. Even some of the A-ranked journals can't be happy about this. However, I'm sure the A*-ranked journals are happy. But, what on earth do these tiers mean? The associated web page is here, but this is the gist of it:

• A* - Typically an A* journal would be one of the best in its field or subfield in which to publish and would typically cover the entire field/subfield. Virtually all papers they publish will be of a very high quality. These are journals where most of the work is important (it will really shape the field) and where researchers boast about getting accepted. Acceptance rates would typically be low and the editorial board would be dominated by field leaders, including many from top institutions.

• A - The majority of papers in a Tier A journal will be of very high quality. Publishing in an A journal would enhance the author’s standing, showing they have real engagement with the global research community and that they have something to say about problems of some significance. Typical signs of an A journal are lowish acceptance rates and an editorial board which includes a reasonable fraction of well known researchers from top institutions.

• B - Tier B covers journals with a solid, though not outstanding, reputation. Generally, in a Tier B journal, one would expect only a few papers of very high quality. They are often important outlets for the work of PhD students and early career researchers. Typical examples would be regional journals with high acceptance rates, and editorial boards that have few leading researchers from top international institutions.

• C - Tier C includes quality, peer reviewed, journals that do not meet the criteria of the higher tiers.

In the field that I mainly work in, and journal types I would submit journal articles to (urban and regional planning, human geography), how does this translate?

Well, here are some examples of journals by ranking tier:

• A* - Urban Studies, Regional Studies, Town Planning Review, Environment and Planning B, Journal of Planning Education and Research, Journal of Planning Literaure, Progress in Planning...
  

• A - Annals of the Association of American Geographers, Housing Studies, European Planning Studies, Environment and Planning A, International Planning Studies, Cities, Environment and Planning D, Planning Theory and Practice...
  

• B - Area, Australian Geographer, Geoforum, Spatial Economic Analysis, Space and Polity, Professional Geographer, Australian Planner, GeoJournal...

• C - Applied Geography, Journal of Geography, Critical Planning, Scottish Geographical Journal, Global Built Environment Review, Journal of Urban Regeneration and Renewal...

Should we be worried? Probably, though some of this is country-specific and many journal ranks would change if this exercise was carried out in other countries. However, a precedent has been set... (and I didn't even mention the conference rankings!)