[Talk-GB] Announcement - OS 1:25k mapping availability for OSM data contributors

[Andy Robinson (blackadder-lists)]

And in my haste I omitted to thank Chippy for his excellent map
rectification/warping and WMS facilities. Apologies Tim.

Cheers

Andy

>-----Original Message-----
>From: Andy Robinson (blackadder-lists) [mailto:ajrlists at googlemail.com]
>Sent: 06 October 2009 3:04 PM
>To: 'talk-gb at openstreetmap.org'
>Subject: Announcement - OS 1:25k mapping availability for OSM data
>contributors
>
>We are all used to drawing in difficult or far away features by referring
>to the NPE 1" to 1 mile out of copyright Ordnance Survey mapping in JOSM or
>Potlatch. Its great for long linear features but for accurate stuff, like
>field boundaries and detailed information about the landscape, especially
>in rural areas, it's not enough.
>
>Enter the OS 1:25,000 scale (two and a half inches to the mile)
>1st/Provisional edition [1]. Which I'm happy to announce is starting to
>make an appearance for the project.
>
>There are two parts to the availability currently. One focused on providing
>it via WMS for use in JOSM and the other as tiles for Potlatch.
>
>The first full sheet (NX88 NW or Dumfries [2]) is available for you to try
>out in JOSM [3]. Just add the URL as a custom WMS.
>
>For the Potlatch tiles RichardF has worked up some code magic that should
>automate the process of rectification and tiling. It may take me a little
>time to get that running and the tiles will probably be served from the new
>dev machine which is not quite ready yet so there will be a further
>announcement on this.
>
>Both the WMS and google format tiles use the same rectification data.
>
>The time consuming part is manually obtaining the pixel co-ordinates for
>the corner gridlines of each sheet (which I have to scan in two halves on
>my A3 scanner). It has to be done manually to get the best accuracy, which
>should be generally 10m once available in Potlatch or JOSM. i.e.
>significantly better than was possible with NPE, though note that its still
>only as good as the OS originally survey it in the late 19th century.
>Anyway, it means that this part is a slow process.
>
>Currently I have around 15% of the published sheets with more arriving
>every day. More would be welcome, either by way of donated maps, scans, or
>funds to purchase more from retail suppliers (higher cost - usually about
>£3 to £8 each). With 2027 sheets in the series cost is a factor for how
>quickly I can grow the set.
>
>I'll keep the index updated on the wiki with progress (both obtaining and
>scanning/tiling) so look out for your area turning up. The majority of the
>sheets I have are for England and Wales. Scotland never had full coverage
>from this series.
>
>Cheers
>
>Andy
>
>[1] "http://wiki.openstreetmap.org/wiki/Provisional/First_Edition"
>[2] "http://osm.org/go/evY0@6R"
>[3]
>"http://warper.freemap.in/layers/wms/1?request=GetMap&version=1.1.1&styles=
>&format=image/png&srs=epsg:4326&exceptions=application/vnd.ogc.se_inimage&"