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Map Projections Part 2: The Allegory of the Cave

In this second post on map projections we cover the range of different types of projections. Part 1 gave us a broad overview of different map projections In thinking about map projections I’m reminded of an old story. Now bear with me on this one: in this story, imagine some prisoners, chained in a cave…

Keeping Your Feet Dry with Mosaic Datasets

Mosaic datasets can be used store and manage a collection of raster grids. We demonstrate this by downloading some high resolution DEMs and the stitch them together in a mosaic dataset. Even as we speak, students in ERST202 are engaged in a fairly big project looking at the impacts of potential sea level rise on…

Don’t Let That Dragonfly Get Away! – Offline Mapping in Vanuatu

Offline mapping provides a way to collect data in the field without an internet connection. In this post we look at how an app is being used to collect dragonfly observations in Vanuatu. Several years back, Milen Marinov was working on his masters degree here. He’s an expert on Odonata species (dragonflies) and as part…

Map Projections Part 1: Where on Earth are we?

We begin a discussion of the pluses and minuses, highs and lows of map projections in this post. We’ll always have problems flattening out our spheroidal earth onto flat maps. Not that I’m a huge basketball fan but I’d like to give Shaquille O’Neal the benefit of the doubt about claiming the earth is flat…

A Shady Topic – Hillshade layers

This post looks at hillshade layers – how they are used and created and how our brain interprets them. I had an interesting mapping experience last winter. While taking a break in the lodge at Mt Cheeseman, I was confronted, yes, confronted, by a strange phenomenon. Now I take a fair bit of pride in…

Can I use my own symbols on maps?

This post covers how to use your own custom symbols in ArcMap I had a good question in one of my classes recently (thanks Jacque!): can I use my own symbols on maps in ArcMap? Short answer – yes! It may not be as easy as we might like, but it’s certainly doable. We’ll look…

What Do Cave Orcs and Riverbeds Have in Common?

In this post we look at how a hand-held laser scanner is being used in the water lab to capture high-resolution elevation data of a scale model of the Waiho River. Lincoln has a long history of using physical models of to study gravel bed river systems, and the West Coast’s Waiho River in particular. …

The Evolution of a Map

In the post, the ongoing process of developing a map with a colleague is documented. For many people, GIS is all about the map. And fair enough, too. Why use GIS if you’re not interested in a map? The final destinations for maps are many-fold but their main intent is to communicate the results of…

Aerial Oddities

This post follows up Image(ry) is Everything and looks at a few apparent anomalies in the image. In a previous post we looked at a high resolution image of post-earthquake Christchurch from 2015-16. We briefly return to that same image in this post to look at a few oddities. In particular, let’s look at part…

Image(ry) is Everything

This post covers obtaining a high-resolution image of post-earthquake Christchurch and creating a mosaic dataset to manage it. It’s that time of year when the students in ERST310/607 are hard at work on their independent GIS analysis projects; this also means a bit of trouble shooting at GIS Central. One student, who is looking at…