[mkgmap-dev] Error writing overviewmap - continue at failure

Sat Feb 27 16:38:29 GMT 2021

Hi Joris,

I will soon be passing an updated patch to Gerd to improve this, as I had
also been experiencing similar problems. The overview map is not built until
all the tiles have been created (assuming the error is not in an overview
tile), and I don't think it uses the style file at that point, just merges
all the ovm data, so using a new style will not help without restarting your
run. The message produced by the patch when the overview file is too big is
"The overview map is too big. The maximum size is 16777215. Try reducing the
highest overview resolution or reducing the amount of information included
in the overview." If you build your own version of mkgmap, you can use the
version of the patch I posted a few days ago. For the whole world, I expect
the maximum resolution of overview to be pretty low. If I build a single UK
county, I can have an overview at resolution 22, but only 20 for the UK. I
haven't tried anything bigger. You may get some idea how close you are to
the limit by totalling the sizes of the ovm files. The maximum size may not
necessarily be the max for the whole file, it may be the limit of a sub file
though. That is certainly the case for ordinary map tiles, but I'm not sure
on the overview.

I also have some code that I'm working on that adds support for a
mkgmap:nooverview tag in the style file, so that if you have overlapping
main and overview resolutions, you can direct your style to omit some of the
information from the overview. Will be passing this patch over shortly as
well.

I don't think allowing a continuation after a failure in the final overview
map would be helpful, as there is very little left to do at that point.
There are some issues with the keep going handling and I'm also looking at
that.

Cheers,
Mike

From: Joris Bo [mailto:jorisbo at hotmail.com] 
Sent: 27 February 2021 14:49
To: Development list for mkgmap <mkgmap-dev at lists.mkgmap.org.uk>
Subject: [mkgmap-dev] Error writing overviewmap - continue at failure

Hi,

I think the below error message is for writing the overview map.
Of which I would not be surprised, it was a test on splitting and building a
full-planet.osm map. So. no worries.

But now I'm wondering if there is a way in which I could continue testing
with the already generated 4.426 img-files and 4.426 ovm_work files to
obtain a .tdb file, mdx files, nsis installer etc.
It took 21 hours for mkgmap sofar, so it would be nice if that time spent
was not useless.
I used splitter with maxnodes 1.700.000 which took another 9 hours and did
not give errors when building a single .img file

I would like to simplify the style-file run mkgmap again on the previous
output and try the create an overview map only (So without building all the
img files again) and this way iterate until I found the breakpoint.
1)     Would that make sense?
2)     Could I enable some more error/verbose logging to obtain info about
sizes/counts or whatever indicators that would help to see if my changes
help in my search to a smaller overviewmap.
3)     Would It make sense to not generate a MapFailedException but a
warning only? So mkgmap would continue finishing the last millimeters to the
finish (off course without a working overviewmap)

Kind regards
Joris

SEVERE (MapFailedException): (thrown in BufferedImgFileWriter.ensureSize())
There is not enough room in a single garmin map for all the input data. The
.osm file should be split into smaller pieces first.
uk.me.parabola.imgfmt.MapFailedException: There is not enough room in a
single garmin map for all the input data. The .osm file should be split into
smaller pieces first.
            at
uk.me.parabola.imgfmt.app.BufferedImgFileWriter.ensureSize(BufferedImgFileWr
iter.java:275)
            at
uk.me.parabola.imgfmt.app.BufferedImgFileWriter.put(BufferedImgFileWriter.ja
va:238)
            at
uk.me.parabola.imgfmt.app.trergn.Polyline.write(Polyline.java:142)
            at
uk.me.parabola.imgfmt.app.trergn.RGNFile.addMapObject(RGNFile.java:140)
            at uk.me.parabola.imgfmt.app.map.Map.addMapObject(Map.java:273)
            at
uk.me.parabola.mkgmap.build.MapBuilder$ShapeAddFilter.doFilter(MapBuilder.ja
va:1459)
            at
uk.me.parabola.mkgmap.build.LayerFilterChain.doFilter(LayerFilterChain.java:
58)
            at
uk.me.parabola.mkgmap.filters.LinePreparerFilter.doFilter(LinePreparerFilter
.java:143)
            at
uk.me.parabola.mkgmap.build.LayerFilterChain.doFilter(LayerFilterChain.java:
58)
            at
uk.me.parabola.mkgmap.filters.RemoveEmpty.doFilter(RemoveEmpty.java:59)
            at
uk.me.parabola.mkgmap.build.LayerFilterChain.doFilter(LayerFilterChain.java:
58)
            at
uk.me.parabola.mkgmap.filters.RemoveObsoletePointsFilter.doFilter(RemoveObso
letePointsFilter.java:142)
            at
uk.me.parabola.mkgmap.build.LayerFilterChain.doFilter(LayerFilterChain.java:
58)
            at
uk.me.parabola.mkgmap.filters.PolygonSplitterFilter.doFilter(PolygonSplitter
Filter.java:81)
            at
uk.me.parabola.mkgmap.build.LayerFilterChain.doFilter(LayerFilterChain.java:
58)
            at
uk.me.parabola.mkgmap.build.LayerFilterChain.startFilter(LayerFilterChain.ja
va:73)
            at
uk.me.parabola.mkgmap.build.MapBuilder.processShapes(MapBuilder.java:1260)
            at
uk.me.parabola.mkgmap.build.MapBuilder.makeSubdivision(MapBuilder.java:901)
            at
uk.me.parabola.mkgmap.build.MapBuilder.makeMapAreas(MapBuilder.java:813)
            at
uk.me.parabola.mkgmap.build.MapBuilder.makeMap(MapBuilder.java:312)
            at
uk.me.parabola.mkgmap.combiners.OverviewBuilder.writeOverviewMap(OverviewBui
lder.java:192)
            at
uk.me.parabola.mkgmap.combiners.OverviewBuilder.onFinish(OverviewBuilder.jav
a:105)
            at uk.me.parabola.mkgmap.main.Main.endOptions(Main.java:675)
            at
uk.me.parabola.mkgmap.CommandArgsReader.readArgs(CommandArgsReader.java:125)
            at uk.me.parabola.mkgmap.main.Main.mainStart(Main.java:144)
            at uk.me.parabola.mkgmap.main.Main.main(Main.java:115)

Met vriendelijke groeten,

Joris Bo
jorisbo at hotmail.com <mailto:jorisbo at hotmail.com> 

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