I often find myself using Julian days as a simple method to represent dates in my code. It’s nice and easy, because every day is simply an integer (the number of days since the beginning of the year) and any time during the day can be represented as a floating point number (the fraction of […]
If you are creating maps then for goodness sake Use sensible colours! I was helping some undergraduates with some work the other day, and they decided to use the following colour scheme for representing river depth: Deep water: Red Medium-depth water: Bright green Shallow water: Pink Why did they do this? Well, either they were […]
As part of the OS Open Data initiative the Ordnance Survey has released a free version of their 1:50,000 scale gazetteer. This lists all of the names shown on the 1:50,000 scale OS maps, linked to information such as their location (in both Ordnance Survey grid references and WGS84 latitude/longitude pairs) and type (city, town, water […]
For a long time I have been searching for a simple, easy-to-use, comprehensive list of freely available GIS datasets that I can use in my academic work – or for any other non-commercial purposes (eg. teaching, ‘just for fun’ applications, etc). All of the lists that I have found have been out-of-date, riddled with adverts, […]
Just a quick post this time, as I’m currently enjoying a nice holiday (well, holiday combined with work) in France. I had to post this because I’ve just realised that one of my biggest gripes with ArcGIS has been fixed in version 10! Hooray! I suspect a lot of other people have been frustrated by […]
Summary: Great book – both for GIS concepts and for teaching Python libraries. Lives up to the boast on the front cover – you really will learn to create complete mapping applications, learning a lot of useful tools and techniques on the way. Reference: Westra, E., 2010, Python Geospatial Development, Packt Publishing, Birmingham, UK, 508 […]
I spent part of today struggling with an undergraduate student to get our university-provided ArcGIS dongle licenses to work. In the spirit of sharing our hard work with the rest of the world, the solution below may be of use to people. The error that we got which were fixed by this solution are listed […]
Quite through chance I just happened to stumble upon the USGS New EarthExplorer, and I’m really quite impressed. Remote sensing is a field that is almost entirely based around new technology: satellite sensors, computer processing techniques and so on, but for ages actually acquiring the data has been an exercise in frustration. Much as the […]
As part of my DunesGIS project I had a need to calculate ‘closeness statistics’ for objects in ArcGIS. By ‘closeness statistics’ I mean statistics giving information about how close the objects are to each other. I needed to do this to calculate how dune patterns change over time. The code below takes a shapefile as […]
No, this isn’t about thinking deeply while the wind is blowing, or philosophising about how the wind is there but we can’t see it – it’s about sand dunes. Now, you might think that sand dunes are quite boring things, just hills made out of sand that sit there and do nothing. That couldn’t be […]