An Embarrassment of Contours
This post discusses how a large collection of contour shapefiles were merged together, dissolved and then a subset of contours were selected and exported. Here’s an example of a relatively quick and easy GIS job that frequently comes across my desktop. Woody from SOLA contacted me with a question about some data he had. It […]
Where This Is No Elevation
This post covers how elevations for dragonfly observation points data for Vanuatu were sourced from a space shuttle mission in 2000. For creatures that weigh way less than a gram, dragonflies have certainly kept me busy over the years. We’ve already seen how my colleague, Milen, used some offline maps on his phone to collect […]
Taveuni – An Island Torn in Two
Spatial data of dragonfly observations from the Fijian island of Taveuni posed some interesting mapping problems . This post covers how we resolved them using a new projection. You may recall an earlier post where we talked about collecting dragonfly sightings across the Pacific. My colleague, Milen, is quite the dragonfly aficionado and has been […]
Contour Labels Made Not So Easy!
In previous posts we looked at deriving elevation contours and creating index contours for display. This time we look at the not quite so straightforward task of labeling our contours. So previously we’ve covered how to derive contours from elevation data and then create some nice index contours. The last piece of this puzzle is […]
Index Contours Made Easy
Index contours help the map reader get a better feel for the topography of an area. Symbolising index contours is easy to do with a little bit of preparation. In an earlier post we looked at creating elevation contours: This time we’ll look at how we can better display our contours by symbolising some index […]
Election 2017: Counting on the Maps
This post looks at mapping the results of the 2017 general election with a particular focus on using cartograms to better represent the results. I don’t know about you, but on election night I was looking for some maps. Sure, a ticker tape of the electorate outcomes across the bottom of the screen was useful, […]
Contours Made Easy
In this post we look at two different ways of creating elevation contours from a DEM. In one we derive and smooth the contour lines and in the other we smooth the DEM first. One of the most common questions we get here at GIS Central is about creating elevation contours. It’s not a difficult […]
Droning on…
This post covers some of the outputs from LU’s new Unmanned Aerial Vehicle, or drone. The university recently acquired a new unmanned aerial vehicle (UAV), or as they’re more commonly known, a drone. It’s an eight-rotor Altus Delta with three sensors: a high-spec Sony camera, a Sequioa multispectral sensor, and a WIRS thermal camera. That’s […]
Turning the Tables on Text
This post demonstrates how to use the field calculator to extract text values from a field and add them to another field. We join our programme already in progress… So here’s the thing – I’ve been doing some more analysis on the proximity of tobacco retailers to secondary schools, focusing on areas within 0 – […]
How to be in two (or more) places at once
Multiple coordinate systems are covered in this post. In these busy, busy times, wouldn’t it be nice to be in more than one place at a time? Good news! You can! In fact you have been ! You’re soaking in it! “How?” you may well ask. All thanks to multiple coordinate systems. This ties in […]
