On 24/07/2020 16:59, Martin Wynne wrote:
I'm looking for some pointers.
I have a dedicated server (located in Ohio, I'm in UK) with full
controls. I'm fairly confident with web sites and javascript (and
geometry), but I'm entirely new to online mapping (apart from editing
OSM in the iD editor).
What I want to do is use OSM as a base map for small areas of the UK,
but remove entirely all the OSM-derived railway tracks, and replace
them with my own data. This data would be essentially fictional, not
based on or derived from anything which is there now. I want to be
able to create tiles zoomed in far enough to see individual rails and
sleepers, with each rail as two separate rail edges.
Where would I start to do that? How would I deal with attribution,
warning unsuspecting users that everything is derived from OSM (and
can be relied on to the same extent, if any, as any other OSM) EXCEPT
the railway tracks, which can't?
Many thanks for any help/ideas/suggestions.
I have done this a few times for my own maps. For a small area I
download the area into JOSM (so you need to setup and learn JOSM). This
allows you to save an area as an .osm file on your local PC. I then
remove, change and add anything I need and save it to the .osm file
again. The crucial thing is to avoid uploading the edited data to the
OSM server, so I disable my credentials in JOSM so that uploads won't
work. You can load, edit and save many times of course to get what you want.
When the map data is how I want it I load the .osm file into a local
database with osm2pgsql (the normal process for making local map tiles)
and go through a rendering process. I still use TileMill, but there are
various other options.
This allows you to invent or subvert any tagging regime you want. You
can use any existing OSM data but also remove (or ignore in the render)
anything you don't want. You can add anything else that suits you.
The map tiles that result from the rendering process can be uploaded to
the usual map tile directory structure on your web-facing server and
then you will need a web page with map code on it to display the tiles.
I always use Leafletjs which is powerful and easy to use if you know
your way around Javascript.
You need to credit OSM in the normal way for any published map -
Leafletjs helps you add a suitable credit on a web page.
Making a map that lets you zoom in so far to be able to see rails and
sleepers on a track is a tall order - I think Leafletjs handles up to
Zoom level 22, but I'm not sure that will show enough detail. At that
level renders of even small areas starts to make very large numbers of
tiles.
I have used this (or very similar) techniques to make map for temporary
events such as fairs, fêtes and festivals as well as a planned scheme of
flood defences and a mock up of a tidal barrier.
HTH
cheers
Chris Hill (chillly)
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