I have access to ESRI Geodatabase and Shapefile: http://www.stats.govt.nz/browse_for_stats/Maps_and_geography/Geographic-areas/digital-boundary-files.aspx. What I need is to somehow get the polygons of the geographic units defined in them as a set of latitude/longitudes. Is this possible? If so, how would I go about doing so?

I'm trying to understand some statistics provided by the organization, but they are divided by "meshblocks". I want to be able to plot these statistics against each geographic unit.

closed as too broad by PolyGeo Apr 30 at 22:23

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    What software/API are you using? Do you have any programming ability? If so, what language(s)? – Michael Stimson Dec 17 '15 at 22:52
  • I can program in PHP. Hopefully there is some tool already available that will convert their data into what I need? I just need a set of lat/lng values to define a polygon that I can overlay on a Google map. I also need to be able to determine if a coordinate is within a polygon. – MapsNewbie Dec 17 '15 at 22:56
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    Are you looking for a software solution to do this? Maptitude Mapping software includes several data layers for New Zealand and also offers the ability to aggregate/ dis-aggregate data to different levels. You would be able to get "centroids" from the polygons described above. There are several other methods as well, but you will need to have some piece of software to help you do it. – Drew Smith Dec 17 '15 at 23:00
  • If you decide to use ArcGIS for Desktop then I think this probably distils down to being a duplicate of gis.stackexchange.com/questions/71685/… – PolyGeo Dec 17 '15 at 23:28
  • Please use the edit button to try and revise it with any requested clarifications because at the moment, especially if your comment is taken into consideration, it is appearing too broad for our focussed Q&A format. – PolyGeo Dec 18 '15 at 0:12

To do this you will need to find a GIS software that can read New Zealand Transverse Mercator 2000 (NZTM2000) and project it into a Geographic Coordinate System.

A similar question has been asked on Stack Overflow as Using D3 to tranform NZTM2000 coordinates to WGS84 but it has not been answered so I am going to suggest that its asker deletes it from there and re-posts here.

  • All the parameters are there to make a projection and transformation file (see linz.govt.nz/data/geodetic-system/… attachment, even some python tools to help) this wouldn't be easy for a novice user but it is possible in ArcGis. – Michael Stimson Dec 18 '15 at 0:06

There are (brand new) web services that give both the meshblock geometry and associated statistics located here. You can click on "services" and get the data as WFS that you can add to Google Maps or any other web mapping API. These services serve data in WGS84 by default (latitude/longitude). This should be a preferred option, unless you really need to download the file GDB, which you can also do from the above link (and avoid reprojection issues altogether):

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If you do still need to reproject, you're looking to convert from EPSG:2193 (NZTM) to EPSG:4326 (WGS84), which should be enough information to work with any reprojection library or GIS software. We can be more specific if you mention which tools you have access to.

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