[mkgmap-dev] I would like a maxways parameter and associated code to limit the number of ways in a tile

Mon May 21 23:45:49 BST 2018

Dear Sirs:

My definition of "ways" was requested.

Splitter first scans nodes (points of various kinds), then ways (forming
lines, paths and polygons) and finally relations (container polygons for
any or all of nodes, ways or relations). I was using "ways" in the same
sense that I understand that splitter uses "ways" in its messages. I
hope this helps.

--maxnodes sets a soft upper limit on the number of nodes in a map tile.

I am requesting a similar in concept --maxways to set a soft limit on
the number of ways in a map tile.

Randolph J. Herber

On 5/21/2018 12:27 PM, Andrzej Popowski wrote:
> Hi Randolph,
>
> what do you mean by "ways"? Any line, road with an address, road used
> for routing? I don't remember if I ever spotted similar problem.
>
> On the other side, I think splitter can be better tuned for current
> mkgmap. I get impression, that splitter is designed to make a good
> work with simple maps and doesn't account for addresses, routing nodes
> od DEM data. It would be nice, if there were more options, than maxnodes.
>
> For my maps, I split OSM data in two stages. First I prepare
> artificial data, that I believe represent better actual size of
> compiled tiles.
>
> I extract addresses as points and highways as simple 2-points lines (I
> do it with modified osmfilter). Then I make splitter to calculate all
> tiles using as an input following data:
> - OSM source
> - 0-2 times extracted addresses
> - 6-10 times extracted highways
> - 1-2 times contour lines
>
> I believe, that additional points form address account for some NET
> size, points form highways for additional NOD size and duplicated
> contour lines for DEM size. It needs some tuning for different areas,
> but I think I get a bit more uniform sizes of img than with direct
> splitting.
>
> On second stage I use prepared areas.list to split real data.
>
> Basically I do something like this:
>
> osmfilter.exe data.o5m --keep= --keep-ways=highway=* -o=net.o5m
> osmfilter.exe data.o5m --keep= --keep-nodes=addr:housenumber=* -o=adr.o5m
>
> splitter.jar --stop-after=split --max-nodes=3000000 data.o5m net.o5m
> net.o5m net.o5m net.o5m net.o5m net.o5m net.o5m net.o5m adr.o5m
> adr.o5m contour.pbf contour.pbf
>
> splitter.jar --split-file=areas.list data.o5m contour.pbf
>
> It would be helpful, if I could do it in a single pass. Maybe splitter
> could filter internally specific nodes - these which would end as
> routing nodes or address information and add some multiplier when
> counting these nodes for splitting? Assuming this is easy to
> implement, otherwise my procedure is good enough.
>

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