Meshblock mysteries solved

By Aaron Schiff 26/03/2015


Previously I posted about some mysteries in New Zealand meshblock datasets, and in particular the differences in the sets of meshblocks contained in the Census meshblock dataset and other geographic data files.

One of the wonderful, helpful people at Statistics New Zealand read my post and sent me a detailed email about these “mysteries”, and with many interesting facts about meshblocks. With permission, I have published this below, in case anyone else is interested in these details.

I had the pleasure of reading your blog ‘Meshblock Mysteries’ and can provide an explanation on why the files you mention differ.

For 2013 Census year the full set of meshblocks, contains a total of 46,637 meshblocks. This total is reflected in the Areas Table txt file.

The 16 meshblocks you list (also listed below) are not digitised and therefore are not available in either the clipped or full digitised patterns.

The clipped version of the digital files also excludes any water meshblocks with an indicator of either Inlet or Oceanic. In addition, Three Kings Islands (mb0017001) are excluded in the clipped file because they are not fully digitised (appearing as a blob) and include a large water component.

The Census dataset excludes those meshblocks in Column A as population count only is collected for these areas.

ND meshblocks

The table below indicates which fields are included or excluded in the differing files.

image001

Using the meshblock dataset with the full digitised pattern will include all meshblocks except the 16 non-digitised.

Oceanic areas are included in the census night population and dwelling counts to account for those person’s on cruise ships. The Statistics Act 1975 also requires information to be supplied on people not living in any dwelling. The scope of the 2013 Census covered every man, woman, child and baby alive in New Zealand on Census night (including overseas visitors) who is:

  • on New Zealand soil
  • on a vessel in a New Zealand port, harbour, lake, river, or ashore
  • on a passage between New Zealand ports.

Metadata for our various geographies is available from our website via the following link: http://www.stats.govt.nz/browse_for_stats/people_and_communities/Geographic-areas/digital-boundary-files.aspx#metadata

Hope this clarifies the mysteries of meshblocks a little more for you.

Editor’s note: we continue to work through Aaron’s excellent back-catalogue of posts.