Found maps of the Waikato
December 27, 2016
I’ve lived in Raglan, Waikato for 18 months now. I’m preparing to move back to Wellington in just under two weeks, which is a bewildering mixture of excitement and melancholy. It involves a new chapter of working from home, although I’m not changing my employer. I will in fact be returning to Raglan regularly for work, so I look forward to getting in some travel as well.
Modelling traffic noise with laundered data
September 1, 2016
I had hoped to have here outputs of traffic/road noise for New Zealands major urban centres, but unfortunately my plans with a volunteering acoustic engineer have fallen through. (If you’re reading this, I’m still interested!) The engineer in question noticed my previous post on scraping data from MobileRoad. He explained to me that the data has great potential for producing city-wide road noise surfaces.
Mobile Road: Valuable Data Hiding in Plain Sight
May 18, 2016
I’ve spent a lot of time recently testing the waters of open transport data in New Zealand. The summary is that there is actually quite a lot of data available, but it’s not easy to find, it’s not readily interoperable, it’s heavily coupled to the NZTA’s own applications, and generally there are severe uncertainties about the rights to use some of it.
Crash Analysis System: Aggregation Wizardry
May 8, 2016
This is a follow-up post to my previous entry, “Crash Analysis System: The Narrative Arc”, in which I describe my on-going dispute with the NZTA about access to a comprehensive record of road-accident data for New Zealand.
Crash Analysis System: The Narrative Arc
April 28, 2016
For several years, up until at least June 2015, the New Zealand Transport Agency (NZTA) published the data underlying their Crash Analysis System (CAS). This included information on every Police-attended road crash or accident in New Zealand, with attendant information on the environment it occurred in, and what was deemed to have contributed to the accident. While the method of publishing this data was primitive,It consisted of one CSV file for each calendar year, with each record in the file heavily encoded. Decoding required automation and a lot of sifting through several PDFs, and a tool to get machine-readable tables from them. An example record is
'Ashburton District','MOORE ST','100','N',' ','WILLIAM ST','201531749','07/02/2015','Sat','2335','EA','CN1V','103A 129A ','M','R','D','DO','F ',' ',' ','C','050','0','0','0','','','1499510','5137544',and yes that whitespace in
'F 'is actually meaningful. it was sufficient for people with a little bit of time to spare (me) and an unhealthy obsession with transportation issues (me) to make use of it. While in many ways it was a good example of how not to do open data, at the very least it existed, so other people could take it and run with it. All the NZTA had to do was sit back and watch, massage new data, and upload a new file every three months.
Geodata web services
January 16, 2016
Bill Dollins has a downright useful tutorial over on his blog for building a straightforward geodata service with Node, Express, PostgreSQL and Amazon RDS.
3D spatial indexes in PostGIS
And even 4D spatio-teporal indexes!
December 19, 2015
I have just watched Paul Ramsay’s (CartoDB) breakout presentation from PGConf Silicon Valley 2015. I love watching these kinds of videos. They’re reasonably short (~40 minutes) so are good while you’re eating lunch or killing time. They also tend to have little nuggets of wisdom to solve “gotchas” that for some reason no one has ever told you about. This presentation in particular has lots of these for using PostGIS. One I did not know about was the ability to specify an n-dimensional index in PostGIS. The typical way to construct a two-dimensional GIST index in PostGIS is to do:
Vector fields of population travel demand
December 6, 2015
I just finished reading an interesting paper by Xintao Liu and colleauges entitled Time-geographic relationships between vector fields of activity patterns and transport systems, in the Journal of Transport Geography.Liu, Xintao, Wai Yeung Yan, and Joseph Y.J. Chow. ‘Time-geographic relationships between vector fields of activity patterns and transport systems.’ Journal of Transport Geography 42 (2015): 22-33.
Algorithms Group at Eindhoven University of Technology
November 29, 2015
New Zealand Spatial Excellence Awards
Reflections following a PostGIS presentation
November 19, 2015
I have just returned from the New Zealand Spatial Excellence Awards for 2015. I was awarded the Postgraduate Student of the Year Award. I’m very slightly tipsy. I also had a very interesting contrasting experience that I think people in the “spatial industry” in New Zealand might be interested in.
GeoServer Quickstart with Docker
November 1, 2015
Spatial isn't that special
November 1, 2015
This may be a strange thing for me to say, given that my postgraduate qualification, and profession is in geographic information systems. But I don’t think that spatial is particularly special. People pretend it is, and then use that to justify the selling of ridiculous desktop software and “enterprise” solutions to problems that Paul Ramsey here shows can all be solved in a single (PostGIS) SQL query and some wrapper PHP script alongside a slippy map.
Parallel geocoding in Python with geopy
September 10, 2015
Geocoding: the process of taking an address as a piece of semi-structured text, and returning a coordinate somewhere on the surface of the Earth. It’s very unlikely that you’re not going to use an online service to do this. This means a few things. Firstly, that you have to decide on a geocoding provider. Secondly, you’re going to have to sit tight while the geocoding takes place. Python can address both of these issues for you.
Mediawatch on the role of data journalism
July 4, 2015
A very interesting interview with Harkanwal Singh, the New Zealand Herald Data Editor.
Landsat 8 Mosaic
June 22, 2015
I noticed this Tweet today, and thought it was such a great example of good a well-designed interface, and actually useful tool. I felt I needed to share it.
The things you see on a journey
A tutorial on GRASS, bash and Leaflet
June 1, 2015
What is a headway?
June 17, 2014
A headway, as used in transit planning and modelling, is typically defined as the time between consecutive services. If you catch a bus that “comes every half hour”, then the service you catch has a headway of 30 minutes.
Commuting and dropping the kids off at school
June 13, 2014
I have recently been fortunate enough to gain access to the real-time information (RTI) for buses and trains in the Wellington region. This is the information that gets displayed in the box at your bus or train stop giving an estimate of how many minutes until your bus arrives. This information isn’t publicly available as a download or as an API, although you can try your luck looking at the mobile version of the Metlink website. Building statistics from that is a different thing entirely. I tried to write a program to scrape the information, but you have to look at each stop individually and “Due”, “2 mins”, “3 mins”, etc. isn’t actually very useful beyond catching your service.
Global Isochrone Travel Time from London (1881)
June 13, 2014
Here’s an interesting historical map that turned up on /r/MapPorn today. Made by Francis Galton for the Proceedings of the Royal Geographic Society in 1881, I find it particularly interesting because it represents the state of international travel only a decade or so after my Scottish and Irish ancestors travelled to New Zealand (via way of Cape Town, where one of my great-great aunts was born en route).
One Day in Montréal
June 12, 2014
This video of Montréal’s transit system fell across my path today, made by Colin Stewart and Ahmed El-Geneidy at McGill University’s School of Urban Planning. I’ve been reading a bit of professor El-Geneidy’s work recently for my own research, and I’ve recently been entertaining the idea of visiting Montréal for an extended period of time once I print a thesis onto a reconstituted tree. Providence?