David, Which NPE WMS are you using. Is it by any change the "nick" version on dev? I get a much better alignment for that area with the re-rectified NPE tiles from TimSC's space at http://dev.openstreetmap.org/~timsc/wms2/map.php?
Cheers Andy >-----Original Message----- >From: David Earl [mailto:[email protected]] >Sent: 07 October 2009 11:23 AM >To: Andy Robinson (blackadder-lists) >Cc: 'Steve Chilton'; 'Shaun McDonald'; 'Frankie Roberto'; talk- >[email protected] >Subject: Re: [Talk-GB] Ordnance Survey 7th series available > >NPE maps have always had major alignment problems which have seemed to >me to be worse in the eastern side of the country. There's also a new >problem, but I don't know whether it is in the JOSM WMS plugin, the tile >server or what. > >Consider three JOSM screenshots: >http://www.frankieandshadow.com/xref/josm1.png >http://www.frankieandshadow.com/xref/josm2.png >http://www.frankieandshadow.com/xref/josm3.png > >The first is Landsat, obviously. It defaults with an offset of about >100m vertically and horizontally in my part of the world (52N 0E) as can >be seen from the obvious course of the road on the satellite images at >the orange arrows. But once the layer is aligned on known points, it >tends to be aligned across the whole working area. > >NPE maps in contrast, in the second one, firstly has a relative >displacement of tiles (about 150m) in JOSM which is obvious in this >unadjusted download. (We also have to add to that that the map sheet >boundaries don't line up anywhere near accurately) > >The third one though shows that even within a single tile, the alignment >drifts extremely rapidly. I aligned the third one with the junction at >point 1 near the top left of a tile, and you can see that at the bottom >right of the tile, the bend I've marked is off by about 150m >horizontally and 115m vertically over a distance of about 1500m - 10%. >All the roads in this area are GPS surveyed (I did them). > >I mentioned this when NPE maps first arrived, but it's never been >addressed. Is it a rectification problem, or a problem of how JOSM or >the WMS plugin scales or displays the tiles? > >The tile displacement problem is recent and I'm sure that will easily be >fixed. The variation across a tile is more awkward I think. > >David _______________________________________________ Talk-GB mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk-gb
