[mkgmap-dev] Documentation improvements for sea processing,

Fri Feb 19 17:55:18 GMT 2021

Hi Gerd,

I've further edited the documentation in the light of your comments - see
below inline.

>- reg. --add-pois-to-lines (and also ----add-pois-to-areas)
>I think the texts (and of course the option names) are misleading. The
program doesn't generate "POI", it just generates additional nodes with
special >tags and the point rules decide what to do with those nodes.
>I noticed this because of the new text "An extra point added by mkgmap at
the middle of the line".
>Really, mkgmap adds a new node for all existing nodes of the unclosed way
AND one extra node for the calculated middle of the way. Some of the >added
nodes may be filtered, e.g. when two consecutive "inner" nodes have the same
Garmin position.

I've removed the references to "POIs" and replaced them with "nodes", and
added a mention of the points file being used to produce the POIs.

>I think the most important thing about nodes created by  the
--add-pois-to-lines option is that the user probably has to add rules to
ignore most of >those nodes.

I've added a sentence to cover this.

>- Reg. "=== Sea Processing options ==="
>I don't like the word "either" in this section. This implies that you
cannot use --precomp-sea together with --generate-sea while the text for
-->precomp-sea says you can.

I've removed "either".

>- The --generate-sea option can always be used to overwrite these defaults:
>generate-sea=multipolygon,landtag=natural=land

The documentation indicates that under --precomp-sea.

>The default tag natural=land tag is also used in the precomp-sea data, and
e.g. generate-sea: land-tag=natural=background can be used to change >that.
No idea why, found this option in the "Openfietsmap full" style together
with these polygon rules:
>natural=land [0x27 resolution 20]
>natural=background [0x010100 resolution 12]

>- I don't understand the sentence "Must be used in conjunction with the
--generate-sea option." for --coastlinefile option. I guess this only
applies >when data like that in "gbcoastline-unfixed.zip" is used.

If you use --coastlinefile on its own it has no effect. You have to use
--generate-sea with it.
I have clarified the sentence. Perhaps specifying --coastlinefile should
switch on --generate-sea=multipolygon like --precomp-sea does.

>- I think the docu for --precomp-sea should point out that one can download
that data from http://www.mkgmap.org.uk/download/mkgmap.html  and >that it
typically is the best option (I don't know any good alternative)

I have added a reference to the URL (I have not made it a link as the
options builder doesn't support links as far as I remember).

>I see no need for a normal user to compile precomp-sea data, but the needed
steps are shown in
>https://wiki.openstreetmap.org/wiki/Mkgmap/help/options#generating_precompi
led_sea_yourself

I do not think mkgmap documentation should reference the OSM wiki (I don't
think it should be referenced on the index page either, as it gives the
impression that the OSM wiki is the prime place for information). If there
is any useful information about mkgmap on the OSM wiki that is not in the
mkgmap documentation, then this information needs adding to the mkgmap
documentation.

Cheers,
Mike

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