mrsid (2016-09-21 01:18:21+00:00): ​​
Hi Graham,

Hamish from NZOpenGIS first sent me the below message, which I used as a guide when I started with importing data a few years ago.
Edited only slightly, for relevance to you.
 Regards
Aydin


if you go to the linz2osm website, http://linz2osm.openstreetmap.org.nz

you'll see links at the top for datasets and layers. the "NZ Mainland" dataset is probably the thing of interest, but it really depends on what you are interested in mapping: your local area, roads, one guy was really into getting all the powerlines up, I'm surprised there aren't more trainspotters doing all the rural train stations, etc. it's up to you where and what you like to do.

the website helps us keep track of what's already been done and prepares data files which can be loaded into JOSM. -- you'll want to install/use/learn JOSM as we make exensive use of the validator tool prior to uploading.

the general workflow is that you log into the site; the first time it will ask you to send a note to the mailing list to introduce yourself to everyone (communication is really really important so we don't tread on each other's toes), and ask for an account. To set up an account we'll need your first and last name and a contact email. (it's hoped in future this can be linked into the OSM accounts, but that hasn't happened yet) also the user account name you'd like (I assume "NZGraham") and we'll give you a temporary password which you can change the first time you log in.

Once you are logged in the interface is pretty much the same, but when you click on a layer there's a link to "Check out data". You press that and then on the map on the right you can zoom in and start highlighting the rectangle areas you're interested in. You can only check out 1000 point features (like trees) or 300 line/area features at a time. Note the OSM mechanics mean that an individual way/line can never be longer than 2000 nodes, so we break them up at 495 to allow for some mistaken connecting before things get ugly. Also a single changeset/upload can never be more than 50000 nodes at a time.

We have been asked by the OSM import gatekeepers to create another OSM account for just the linz data uploads, then keep your personal edits separate. see http://wiki.openstreetmap.org/wiki/LINZ#Import_Process

I guess yours would be like "NZGraham_linz" or so.

So once you're happy with the selected features, you click the checkout button and the server prepares you a .osm file to download. Save it to your harddisk and then load it into JOSM. (or drag the download link directly into JOSM)

I then usually add an Imagery layer for the OSM Mapnik layer to see what's already there, and turn down it's opacity to about 60% so it doesn't intrude on the new data so much. If it is in a city centre I'd usually also manually download the area as a new layer, validate and clean up what's there, and hunt for conflicts. (there's also a merge conflict tool you can try on the linz2osm site).

There are several strategies re. merging, keep an eye out for source=GPS as something you can trust, and note the LINZ data is often better aligned than the Bing imagery. A good thing to do is look at the NZ Geodetic marks dataset, and upload some trig station marks in your area if it needs it. Then look for one of the trig stations in the Bing imagery and use the Image -> align tool to move the bing imagery around until it lines up better. it may be warped not far away, but it's better than nothing. Also it is possible to connect to LINZ's WMS server, so to have the 1:50,000 topo maps as a backdrop image in JOSM, so you can see how it all fits together.

See the osm wiki LINZ pages for tips on uploading, keeping it to 750 nodes per slice seems a good compromise as often the osm server coughs and misses one and needs to retry.

I start JOSM from the command prompt as it spits some information about uploads to the screen there, including the workslice number. That gets cut and pasted into the linz2osm website on the workslice page. you have to enter in some sort of comment to get that to stick, I usually just put a "-" or something if there's not much to say about what needed to be merged, deleted, etc.

for items which are better in OSM than in the LINZ data, I usually don't upload the LINZ one and add a "LINZ:merged=ver 2012-06-06" tag (or whatever version of the LINZ data it is). Typically the LINZ data is better though, so you can remove or retag what was there before if it is going to be directly replaced.

The various layers (coastline, forests, cliffs, rivers) often line up exactly with each other, so manually refitting to what's there means you won't be able to automatically merge the nodes later. I usually wait until all the important layers for an area are uploaded and merged before I'd start fine tuning the new/old data to fit each other exactly. Having said that, it's a good idea to keep waterways and coastline not overlapping, I'll usually move the old feature out of the way a little so that it doesn't overlap the new area.

ok, that's a long email but really it's pretty self-explanatory and quick once you get into it.