GIS Blog

I Can See For Miles and Miles and Miles

Viewsheds are useful layers that allow us to model visibility of features on the surface of the earth.  In this post we look at the effect of the curvature of the earth on these raster layers With due homage to The Who, this post goes out to all those who adhere to the crazy idea…

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Paths to Good GIS: Default Workspaces

Setting default workspaces is a good data management habit to get into – it may save you lots of heartache when saving new layers. There are lots of things that contribute to doing good GIS work, and practicing good file management has to be near the top.  Anyone who has done any amount of GIS…

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Fixing Common ArcGIS Problems

This post covers some of the common problems that arise with ArcGIS, and how to fix them. There’s no getting around the fact that GIS is frustrating.  And it doesn’t get any better as you do; the problems just transmogrify into different kinds of challenges.  In this post we’ll look at the top five common…

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Lost in the Arctic

In this post we look at a challenging map situation and how some cartographic choices got in the way of a good article. While perusing the web recently, I came across an article on the lack of ice regrowth in the Arctic this year.  It’s highlighting that at this time in the northern hemisphere, sea ice should be…

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Eye Popping Details from LiDAR Data

This post covers some of the amazing detail contained in newish LiDAR-derived DEMs for Canterbury. LiDAR has popped up in many posts here – and rightfully so.  It’s not too much of an overstatement that these data are revolutionising terrain analysis.  I thought it might be enlightening to show some of that detail from a…

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A Cautionary Tale of Tahr

A simple mistake crept into a map just recently so this post is a cautionary tale about being very thorough about checking all aspects of your map before it is “done”. This post is written as a cautionary tale.  Here’s the background.  I recently got an email from Geoff Kerr, who serves on the board…

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Loaded Layers

We look at using the Load command to add new records to a layer in this post.  Sometimes it’s a far better option than a spatial join or a merge. We recently had a summer scholarship student looking at some mapping work for the Department of Conservation (DOC).  Amongst the myriad of things they look…

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Some Very Cool Data

This post reviews LiDAR data available for the southern continent and the Dry Valleys in particular.  From the raw data we derive a high resolution DEM. I hate to say this, but some data are cooler than others (Ed. What a geeky thing to say…)  and LiDAR data certainly fit into that category.  We’ve talked about LiDAR earlier –…

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Save your marriage – use layer files

Layer files are a useful way to recreate legends and get consistent symbology.  This post outlines what they are and how to use them.  Geology…who doesn’t love geology?  And who doesn’t love geology maps especially?  (Ed. – Only heathens…)  The image below shows one of the  1:250,000 scale geology maps that cover the country, produced…

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Another Point on the Map (Part 3)

Quality assurance is crucial when creating new data, especially with geocoding.  We cover some of the frustrations of this process and some useful tips (definition queries and label scale ranges) to make it a bit easier. I can safely say that over the past few days I have been almost everywhere in New Zealand: from…

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