[OSM-talk-ie] Two out-of-copyright maps of Ireland now available for OSM usage.

[Donal Diamond]

The GSGS map is now live in Potlatch2 under the name "Ireland - NLS
Historic Maps"

see http://wiki.openstreetmap.org/wiki/Potlatch_2/Primer#Background_Image
 for how to load and realign background imagery.

> +1 from me! I've been waiting for ages on ebay for an ooc map of Longford
> that was 1"/mile or even 1/4 inch

And now you have both! Glad you find them useful.

> Would I be right in saying that to use these to trace missing roads we just
> need to right click on the WMS layer and add a new offset the drag the maps
> so it matches up locally as best as possible?

Yes, in Josm you'll need to drag the map so it lines up with known
good ways or gps tracks. You can also save the off-set bookmark.
However the offset will change even when you pan over to a small area
so the offset bookmark may not be that helpful.

Bear in mind though that I used OSM data for many of my control points
when georeferencing so just because an OSMway and the  background map
agree doesn't mean that it is correct.


>
> And finally, should I be adding a
> source_ref=http://geo.nls.uk/maps/ireland/gsgs4136 or similar tag?

Potlatch2 is currently configured to use a source tag of "NLS Historic
Maps" - there's a shortcut to apply this quickly to a way - select the
way and press "b".

So in Josm, I suggest we use the same souce tag that P2 uses.

This will also allow us to monitor usage using the Irish taginfo
instance: http://taginfo.openstreetmap.ie/search?q=NLS+Historic+Maps#values

D


>
> Thanks again,
> Karl
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