How to make symbols visible on a lesser zoom level

Question

Hi!

Basically I followed instructions from here: http://openstreetmapserverwindows.blogspot.com.eg/2015/11/osmopenstreetmap-tile-server.html to set up our own OSM server on Windows Server 2012 64-bit.

I edited generate_tiles.py and generated some tiles for Tuam town in Ireland to test this. I noticed that there are not many symbols included on zoom level 16, but much on zoom level 17 , below: notice this is the same crossroad:
alt text

However we don't want to generate zoom level 17, because it takes an awful long time to generate so many small tiles even for a small town and we accually don't need such high zoom level. Instead we want to have ALL symbols to be included on zoom level 16 or even earlier. How to achieve this?

Thanks :-)

Answer 1

I would not recommend rendering zoom 16 with all the icons of zoom 17, as the style is carefully crafted to display as much information as possible while keeping clarity. But if you really want to, you should check openstreetmap-carto, the commonly used style, that you would have to modify.

My first advice would be to run a Linux VM in HyperV (or other virtualization), it's free and easy to set up. Then you will a much more common setup and you will be able to find a lot more help !

For exemple you could follow this kind of tutorial (there are many) : openstreetmap-tile-server-ubuntu-16-04 Or the "official" switch2osm.org.

With this kind of setup, tiles will be rendered on demand. Except if you force a render, as in the last step, in the first link they only pre-render down to zoom level 10. Then you can cheaply host a renderer that goes down to zoom 20 ! This way tiles are only calculated when someone needs them, and you can choose to store them or not.

There are probably ways to do the same thing with Windows, but I didn't find it quickly.

Sorry as I don't really answer to the question asked. But I really think it will be easier with Linux to find documentation.

Regards.

Answer 2

Firstly, note that the map style you are using from SVN is about four years old. Since then, all style development has happened in github.com/gravitystorm/openstreetmap-carto - so don't be surprised if your maps look very different from what you see on openstreetmap.org. However, switching to the newest style would also require newer version of Mapnik and osm2pgsql than referenced in the blog article so maybe youre safer to stay with what you have.

You can change the zoom level at which icons are displayed by modifying the right map style file. For example, the file inc/layer-amenity-points.xml.inc controls when amenities are shown. In there, you will for example see a section like this

<Rule>
   &maxscale_zoom17;
   <Filter>[amenity]='fast_food'</Filter>
   <PointSymbolizer file="&symbols;/fast_food.png" placement="interior"/>
</Rule>

Change to &maxscale_zoom16; and you're done - for fast food joints. You can of course do a search and replace too.

How to make symbols visible on a lesser zoom level

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