GIS Blog

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Where the Wild Sub Clover Grows

This posts looks at being mindful of creating ambiguous results in your spatial analysis, in a raster context The GIS Team recently did some work with Sonya Olykan and Derrick Moot on a North Island dryland farm.  The aim was to identify where subterranean clover might be best  grown on the Tokaroa Farm, near Martinborough. …

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Being Fair to Covid-19

We take a look at mapping Covid-19 cases in New Zealand and how we can ensure that our interpretations are more realistic.  MOH figures in this post are current as at 10 May 2020 at 9.00 As we shift a bit closer to Level 2 and a perhaps bit more freedom, it may be an…

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Turning the Tables on Tourism

This post covers how a map of tourist spending for 2019 was done.  Table joins were a critical part of this.  We also look at the mapping process and, more specifically, how to add pie charts to your map. Tourism, as the most significant industry in terms of foreign exchange earnings, is one of the major sectors of…

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Two NZs?

New Zealand often suffers from being overlooked on world maps.  At least one map has tried to reverse that trend. When it comes to world maps, NZ has a problem.  We often get forgotten!   So much so that there’s a whole section of the internet dedicated to documenting this.  One doesn’t need to look very…

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Join the Band (Combinations)

Most satellite images have multiple bands.  We can change the way an image is displayed to highlight certain features in the images. With kudos to Little Feat’s Join the Band album, we’ve been looking at satellite images a lot recently and have seen how many satellite images are composed of multiple bands, or layers.  When working with…

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The Paint-By-Number Tool

We can use remotely sensed images to extract useful information about the land surface using image classification.  The first step is usually segmentation, which groups pixels with common properties together.  This post is a quick look at what it is and how to do it. Ah, a nice, relaxing paint-by-numbers landscape for a Friday.  While I’d…

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The grass is always greener, isn’t it?

This post looks at the NDVI vegetation index that can be derived from multispectral images and give us useful information about the state of plant health for an area. We’ve been talking about satellite images recently and in this post we’ll start going over some of the beneficial information we can get from those images…

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Enhance!

In remote sensing analysis, the higher the image resolution the more valuable the asset.  In this post we cover pansharpening, the process of using high resolution panchromatic imagery to improve the resolution of coarser multispectral imagery. I’m not a big fan of all those CSI-type shows, especially when it comes to their treatment of images. …

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Wavelength(s)

Remotely sensed images are incredibly useful sources of GIS data.  In this post we begin looking at using satellite images to create useful GIS data. Without giving too much away about myself, one of my top five absolute favourite Van Morrison songs is Wavelength, from the 1978 (egads!) album of the same name.  It might…

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Deleting Smokers – Part 1

This is the first post in a series covering the development of a Python script to carry out some analysis.  We cover the idea behind the script and develop some pseudo-code used to flesh it out. For those of you having trouble sleeping, this post may be the one for you.  In several previous posts, we’ve…

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