[Talk-ca] GeoBase Import - Where we stand now

[Steve Singer]

On Sat, 6 Dec 2008, Steve Singer wrote:

> Do we have a handle on:
>

To attempt to answer my own question.

> a) How many tiles have 0 OSM roads (but do have at least 1 road in the
> geobase nrn)

It looks like 245 of the 250k (4 digit) NTS tiles have at least 1 'road' in 
OSM (see note 1).

I do not yet know how many NTS tiles have at least 1 road in geobase (I 
don't have all the data downloaded).


> b) How many tiles have OSM coverage similar to Tofino BC (or any your other
> examples from above) , and how much manual effort does it take someone in
> JOSM to manually fix up the duplicate ways following a OSM import.
> c) How many tiles (that have roads) are left over?
>

The Tofino BC is part of the 'Port Alberni'  250k tile 092F.  It has 103 
roads and is probably a good divider for discussion.

8 Tiles have more than 1000 roads in OSM 
(TORONTO,OTTAWA,QUEBEC,MONTREAL,KITCHENER,DETROIT,VANCOUVER)

40 tiles have more than 100 roads in  OSM.

105 tiles have 20 or more roads.

Breaking the analysis into the smaller 50k tiles shows that only 50 of the 
smaller tiles have more than 100 roads.



I think Dale pointed out that the NRN is segmented by province not NTS tile. 
This is true but a province to too large of an area to deal with as a 
single 'work unit'. The NTS tiling system seems like a reasonable way of 
breaking things up (geobase distributes the larger datasets like the hydro 
network by nts tile id).

Notes:
1. 'road' means anything that the osm2pgsql program adds to the '_roads' 
table and has a non-null highway attribute. 
2. This is based on recent (downloaded Dec06/08) canada.osm snapshot.

Steve