[Aust-NZ] NZ Geo Placenames

[Peter]

Some might remember my last attempt to produce a towns list for NZ.

Im about ready to start a mark 2 version based off of the LINZ placenames shapefile layer.

http://www.ew.govt.nz/Environmental-information/REDI/881334/
Best outlines the issues with this layer, namely that the coords are not accurate.

Ive made a preliminary review and comparison of the accuracy of the following datasets.

geonames
linz geonames
opengps
google
osm

See here: http://www.zoneblue.org/files/coord-comparison.pdf

And conclude that most are poor and none really accurate. My proposal as it stands then is to take a subset of linz GEOGRAPHIC_NAMES namely DESC_CODEs:

METR (4)
TOWN(51)
POPL  (261)
SBRB (570)
LOC (3446)

and geocode them manually using some combination of the TOPO50 rasters, google satmap, and zenbu POIs to determine the best present geographic center of each place. Im hoping/assuming that by using these sources as a visual references only, that an accurate and liberally licensed dataset can be released, without recourse to google geocoder which i used previously.

Im expecting the first 800 odd to be easy enough, then harder after that as the places become more amorphous. We shall probably consider that a bonus if the last two groups happen anywhere near 100%.

As far as attributes go, the plan is to include all the present LINZ attributes, plus District and Regional council, and updated coordinates. Seeing as i will literally be looking at each one, some sort of area figure might be doable by drawing a rough polygon on each place and/or in conjunction with LINZ res_area_poly, or oliver and co's urban areas layer. Ive tried without success a few times to get QGIS to open the large StatsNZ datasets, and QGIS crashes, but from the online version, their boundarys are not always urban/rural. hence, that useful?. However if it could be tapped into population would be the prize.

If anyone has any thoughts before i begin let me know. Im still half expecting a viable source to materialise but, unbelievably, after all these years, it hasnt.

However its clear that better data does exist, as evidenced for example by zenbu. Google geolocation incorrectly places the small town of winchestor, canterbury by about 1km to the east. Zenbu places it pretty much right.


Regards

peter