Re: [mapsforge-dev] Updated Coastline in world.map - Ireland is flooded?

[Emux]

On 07/04/2015 12:31 πμ, lele wrote:

I noticed that in the current world.map Ireland is completely underwater. Is it just me?

Unfortunately I can confirm that :(

I suspect something went wrong at simplification.

I found this option for the maprwiter/osmosis, but not sure it is correct.Didn't recognise the coastline-mode

There was an older fork of map writer trying to handle properly the coastlines, but I think it does not maintained anymore.

Eventually we preferred the mush easier approach with land polygons from OpenStreetMap Data.

--
Emux
Cruiser - Atlas

[Dominik Pfennig]

It seems like this problem consists. to the current version.

I don't know at which point Ireland is getting lost.

After converting the ".shp" to ".osm" with 

https://github.com/mapsforge/mapsforge-mapcreator/blob/master/shape2osm.py

There is already no coastline data for Ireland. That's why the resulting Mapfile has no "natural=nosea" for that area,too and thus displaying "natural=sea".

Is it the data missing in the original shape file or is something going wrong when converting the data to ".osm"

[Emux]

Downloading latest land polygons from OpenStreetMapData and:

- Following the procedure in map creation guide
- Or using the new mapsforge-creator

Can build Ireland with proper coastlines, like seen in ireland.png screenshot.


Have you followed exactly the mentioned steps?

Can always test the cut coastline data shp files with QGIS, as seen in land.png screenshot.

BTW with what map library you show the map file, with Mapsforge or VTM?

--
Emux

[Emux]

If you mean the world.map then probably should use another tool for the conversion of whole world shp -> osm, like those mentioned here in the guide.

--
Emux

[Dominik Pfennig]

Just found the error.The Map creation guide works as expected.

I used to use the provided world.map from your download servers as additional map file that prints the background for the data that is not contained. (Currently I only use the europe dataset)

That way you could see the shape of the land outside of europe rather than nothing.

But the world.map under http://ftp-stud.hs-esslingen.de/pub/Mirrors/download.mapsforge.org/maps/world/world.map is corrupt for ireland.

If you download it and just load this mapfile everything is displayed fine but ireland is not. ( see the attached screenshot; it's just the world.map file loaded )

I then followed the map creation guide and added the land.osm and sea.osm to the europe.osm.pbf and the resulting mapfile displayed ireland just fine.

I will keep the world.map in the multimap datastore but additionally use the land.osm and sea.osm in the europe map file.

BTW with what map library you show the map file, with Mapsforge or VTM?

I have written a simple but fast TileServer that runs on one of our servers. It uses Mapsforge as backend to generate the tiles. The map is then shown with openlayers.

I did that to provide an app that's running with an online service by default but provides an optional download functionality to be run offline, too.

[Emux]

> But the world.map under http://ftp-stud.hs-esslingen.de/pub/Mirrors/download.mapsforge.org/maps/world/world.map is corrupt for ireland.

Thanks for the report, I can confirm that.
It's been some years since we created the world.map to recall the exact process for the shp -> osm conversion.
But shape2osm.py can have issues with world / continent scale polygons, so probably a different converter is needed here.

> I have written a simple but fast TileServer that runs on one of our servers. It uses Mapsforge as backend to generate the tiles. The map is then shown with openlayers.

Very interesting, also in applications list can find other tile server implementations.

> It uses Mapsforge as backend to generate the tiles.

Do you mean generate raster bitmap tiles, e.g. 256x256px ?
Have you seen less labels / symbols than expected or cut labels / symbols at tile edges?

Mapsforge in its MapView uses an internal cache in order to render properly labels / symbols which exist at tile edges.
And there is always the extra label layer option, in order to improve further that situation.

VTM using OpenGL with its own separate renderer, doesn't have such problems.

--
Emux

[Dominik Pfennig]

But shape2osm.py can have issues with world / continent scale polygons, so probably a different converter is needed here.

Yes that seems to be the issue. I will try to generate a working world.map with the  other tools in the next days.

Do you mean generate raster bitmap tiles, e.g. 256x256px ?
Have you seen less labels / symbols than expected or cut labels / symbols at tile edges?

Exactly. I did have problems with cut labels but the current TileServer does not have that problem anymore. I think it's just because I did something wrong with the threading.

Although each Tile gets generated in its own Thread they all use the same DatabaseRenderer. This probably means that all Tiles are generated on the same Thread in the end.

That will lead to scaling Issues. Currently we don't serve more than a million Tiles per day. But it defeats the cut label problem.

When it's time to scale I plan to start multiple TileServers but use the same instance for each user. This can be achieved pretty easy using apache and should come around the cut label problem since Tiles that are grouped together will be generated by the same process.

Or I will give the label Layer a try later on. 

All of that is currently work in progress and not yet finished but if you are interested and want to have a look you can find my project under

https://maps.metager.de

Sourcecode available under:

https://gitlab.metager3.de/open-source/TileServer (TileServer)

https://gitlab.metager3.de/open-source/MetaGerMaps (WebApp)

Contribution to every used Software will of course be given.