GIS Blog

Near and Deer Ones

In this post we look at addressing a spatial problem, coming up with an approach and implementing the solution.  (Spoiler alert – it worked, but not as it was supposed to.)  We often get emails here at GIS Central asking for a bit of assistance with things spatial.  One never knows what will come through…

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Master of Your Domain

We look at how to use attribute domains to enforce some data integrity. Who’s a good consistent typist?  I’m ceratinly certainly not.  Let’s say you had to add a bunch of data into a spreadsheet, maybe names of students and their degrees.  If you’re anything like me, it’s hard enough to get names correctly typed…

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Care and Feeding of Polygons

We look at different editing tools for working with vector polygons in this post. Digitising (creating and editing vector features) is a key GIS skill.  Most find that it’s also one that can be more than a bit frustrating. Yes, we’ve all been there… At the risk of damage to your machine (and psyche), we’ll…

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Profiles in Curvage

Here we look at creating elevation profile plots from high resolution LiDAR data. In a previous post we looked at some elevation profiles using LiDAR data, like this one: On the map we have a hillshade layer from a 1 m resolution DEM derived from LiDAR .  The blue line was drawn from north to…

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Ngā Pūrākau o Te Whenua – Kaitorete Spit

Satellite images, DEMs and hillshades are used to help tell the story of Kaitorete Spit and Te Waihora/Lake Ellesmere.  Thanks to Lloyd Carpenter for guidance on this post’s title, roughly translating to “A Landscape Story”.  Ngā mihi e hoa! Oh great…  Yet another featureless, boring Canterbury vista…(nice day, though) You could certainly be forgiven for thinking this!  We’re…

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Level 4 Exercise

We use a bit of network analysis to set the extent of exercise during lockdown. So you now know that part of my coping strategy for lockdown is Stuff quizzes, but to be honest, the main strategy for me is exercise, and running in particular.  I’d be lost without it, as those in my bubble…

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Three Geographic Strikes

So one of my guilty pleasures is doing Stuff’s two daily trivia quizzes.  That and crossword puzzles.  And…well you probably don’t want to hear about the other ones…  (Ed. Thanks).  Now Stuff has started up a new quiz called Three Strikes.  In this one you get six or seven things that need to be arranged…

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Jacinda’s Heat Map

We look at recent heat maps in the news and work with some publicly available Ministry of Health data on Covid. In a recent Covid-19 update, the Prime Minister showed us a “heat map” of Covid-19 contacts. Be still my beating heart!  Maps to the rescue!  Imagine if she had read out a list of…

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What’s so primo about the Prime Meridian?

The prime meridian sets the zero point for measuring longitude.  What’s so special about it? The Royal Observatory, Greenwich. https://www.mylondon.news/whats-on/family-kids-news/greenwich-royal-observatory-opening-prices-15205328 In the GIS courses we’ve recently been talking about coordinate systems and their importance in GIS.  They are absolutely fundamental as they allow us to do one of the key things that makes GIS useful:…

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On the Edge

We look at creating a catchment boundary layer using existing data and nice visualisations. So imagine you’re walking along a mountain ridge (like the one shown above from Antarctica – hope you’ve got your thermals on).  When it starts to rain, water flows to one side or the other, depending on where it hits the…

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