I have submitted a ticket to the JOSM developers. The ticket contains a fully
worked-out patch to upgrade the EPSG:27700 projection from the Helmert
transformation to the look-up table transformation.
I'm afraid this is another somewhat long and technical message. But it does
contain an
The test will be, if Rob is able to produce example areas processed with the OS
look-up table transformation, do the misalignments go away?
Sorry for a rather long and technical message.
I've done some more investigation and testing. QGIS reckons EPSG:27700 is the
OS look-up table
Hi,
On 27/10/2020 06:18, Adrian via Talk-GB wrote:
I agree with Rob that the misalignment of 5m is obvious if you look at Hugh
Town (Scilly). Both if you compare with the OSM data and if you compare with
the tracklogs that have been uploaded to OSM. So this transformation won't do.
I think
I can confirm that the Land Registry wms parcels appear to have been converted
with the Helmert 7-element transformation (no look-up table). This gives a
misalignment of up to 5 metres. It's ironic that the Land Registry don't seem
to know where their parcels are to better than 5m.
Now we
Hi all,
A few more tiles added to help test the alignment. I've added the following
locations:
# Colchester
bbox = (0.8895, 51.8831, 0.9190, 51.8974)
render_tiles(bbox, mapfile, tile_dir, 17, 17 , "Colchester")
# Flamborough
bbox = (-0.132106, 54.102325, -0.111807,
Thanks for this.
I'm still confused as to what exactly I need but at least I can run some
tests using these places. If it helps anyone, below is the xml we are using
in Mapnik. The Map srs is from the OpenStreetMap default render and relates
to the web projection. The Layer SRS is the standard
With regard to the discussion on the best transformation, OSM recommends that
all transformations from OSGB36 to WGS84 should be carried out using a
3-parameter transformation which is accurate to 21 metres.
(https://wiki.openstreetmap.org/wiki/Converting_to_WGS84#Great_Britain
The Ordnance Survey provides a transformation between OSGB36 and ETRS. It is
described on this page https://www.ordnancesurvey.co.uk/gps/transformation/ and
on the pages linked from there. The transformation is definitive. In other
words, OSGB36 is redefined as being what you get when you apply
Hi all,
To address this and some of the other questions:
>Can JOSM and iD display Mapbox .pbf vector tiles?
I don't think JOSM can which is a big shame as it would make it much easier
to host these sort of layers with minimal overhead.
>ensure any transformation from OSGB grid coordinates to
Hi Rob,
Good stuff, it's definitely worthwhile. Thinner lines could work better
(for me 1px would be perfect), especially that the max zoom stops at 17.
You could perhaps consider increasing the max zoom a notch as well.
Are the numbers in wms tiles UPRNs? If so, you could consider
On Sat, 17 Oct 2020 at 00:22, Rob Nickerson wrote:
> Just in time for the AGM, I have just published OSM UK's first tile layer. No
> don't get too excited it is not a full map render. Instead I have produced a
> very simple tiling of the Land Registry polygon data now that this is under
> the
Nice one. I've been wanting to do this for ages.
Re: file size. Can JOSM and iD display Mapbox .pbf vector tiles? These
would be smaller.
On Sat, 17 Oct 2020, 00:22 Rob Nickerson, wrote:
> Hi all,
>
> Just in time for the AGM, I have just published OSM UK's first tile layer.
> No don't get too
Hi all,
Just in time for the AGM, I have just published OSM UK's first tile layer.
No don't get too excited it is not a full map render. Instead I have
produced a very simple tiling of the Land Registry polygon data now that
this is under the OGL Open Data Licence. My view is that this is a good
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