Orderly Streams

Stream order is a way to categorise river reaches by size.  In this post we see how to add stream orders to a derived stream network. As the temperatures warm up, the tramping season has already gotten underway in our house so keen daughter Islay recently dragged me up the short but steep track to Carroll Hut […]

Burning the Streams

Here we talk about how GIS can be used to create catchment boundaries and river lines from elevation data. Far be it from a surface water person like me to advocate for burning streams in any way (we’re not talking about the Cuyahoga River here), but in a geospatial sense it can be a good thing. […]

Zones of Influence

The role of polygon zones in our lives is up for discussion with a zinger at the end. The image above should raise a number of questions.  What am I doing in the middle of a busy street? for one.  And what does busy Barrington Street have to do with anything?  Note a subtle difference […]

Sometimes Simple Is Best

When faced with a potentially challenging task, a simple tool made it all possible. Sometimes using a simple tool can make all the difference.  While working on a recent project, one of my colleagues needed some data from the River Environment Classification (REC) dataset, developed by our good friends at NIWA.  This is a really useful […]

Come On Up For The Rising

With props to Bruce Springsteen, another post looking at elevation profiles. We had a tramping related post not long ago and here’s another one.  Sometimes tramping is just idyllic with fantastic views, good mates and serene moments.  Other times, well it’s just a plain, hard out slog of putting one foot in front of the […]

Spatial join- the tool you need

Ruby gives us some more insight into the Spatial Join tool. Spatial join: the tool you didn’t know you need (but it’s exactly what you’re are looking for). When I was completing my final project, I found that I had multiple layers with a heap of data on each, but I couldn’t really do much […]

Shady Intersections

We look at using the Tabulate Intersections tool to do an off-beat spatial join. Postgrad Lucia had a problem, a spatial problem, to be more exact.  As part of her MLA she’s doing some research on whether shade is equitably provided in Christchurch’s parks, i.e., do wealthy neighbourhoods have more access to shade than poorer […]

Of Graticules and Grids

In this post we look at adding grids and graticules to maps I hope it’s not too much of an exaggeration to say that most people who like GIS also love maps.  I mean love maps.  Okay, at least I do.  With the tramping renaissance going on in my whanau, that has gotten us focused on […]

Viva la Resolution!

We look at the impact of resolution on raster data. More often than not, the first question asked when dealing with raster data is, “What’s the resolution?”.  Here, resolution refers to the size of each grid cell, or, if we’re talking about imagery, each pixel.  Since each grid cell is a square, we can further […]

Some labels are better than others

In this post we look at some clever contour labelling to make your maps sparkly with masking. We’ve been talking about map making in the GIS courses recently, which shouldn’t come as a surprise to anyone.  Making effective maps to communicate your analysis results is an essential GIS skill.  In one class we were looking […]