Phillip Pearson - web + electronics notes

tech notes and web hackery from a new zealander who was vaguely useful on the web back in 2002 (see: python community server, the blogging ecosystem, the new zealand coffee review, the internet topic exchange).


Mapping New Zealand, online

Mikel Maron contacted me recently about adding more precise location data to cafe entries on the New Zealand Coffee Review site.

I replied that I would love to... if I had a) a way to find the precise location of each cafe, and b) a way to present it.

Mikel pointed me to the New Zealand Open GPS Maps Project, which seems to have a lot of data. It's GPL-licensed. I think the license covers the work Graeme Williams has done to combine a bunch of free datasets and put them in Garmin format though, rather than the original datasets, which I might be able to use.

But then - hey - what's this? seems to have a pretty decent view of New Zealand! Here's Cathedral Square, the centre of Christchurch, for example. I guess this is what I want :)

Update on Graeme's sources: Graeme's data originally came from the New Zealand Topographic Database. This costs $1500 for 12 gigabytes of maps - ouch! However, Olliver and Company distributes it for $800, or $200 for the 2001 data. Graeme is using the 2001 data, which also has a much less restrictive copyright.

New discovery: NZTopoOnline has a map-providing web service!

Update: You can download reasonably big chunks of map data from NZTopoOnline's web-based viewer.

Here's how:

  1. Click "I agree to the terms and conditions", then drag the mouse over a region to zoom in on it.
  2. Do that a couple of times until the map is centred on the area you want to export, then click on the magnifying class with an 'S' in it ("Zoom to user specified scale") and click "Zoom to" in the popup to zoom to 1:50000.
  3. Now click the button with a red arrow pointing to a hard disk ("Custom extract") and click on "layers to be extracted" in the popup.
  4. Check as many boxes as you feel like, but don't forget Road_cl if you want to see streets and street names.
  5. Now click "Extract" and download the file from the "Download" link that appears after extraction finishes.

You can view the downloaded data using ESRI's free ArcExplorer application.

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