[Xastir] OSM map north-america-latest.osm

[Guy Story]

Thank you Tom.

Sent from Guy's iPhone

> On May 29, 2023, at 13:50, Tom Russo <russo at bogodyn.org> wrote:
> 
> On Mon, May 29, 2023 at 12:56:55PM -0500, we recorded a bogon-computron collision of the <kc5goi at gmail.com> flavor, containing:
>> I have been away for a very long time so I am sure this has been asked but
>> I am not finding the answer and I am not 100% sure this is feasible. I did
>> a fresh installation of 2.1.7 on a fresh Ubuntu installation. I have
>> downloaded and extracted north-america-latest.osm from Geofabtrik. I am not
>> seeing how to put it in service. I moved the extracted file to
>> /usr/local/share/xastir/maps/Online but it does not show up in the map
>> list. Am I missing a geo file or is this not supported or practical since
>> it is a huge file?
>> 
>> Normally I try to cache an area I am going to be in ahead of time in case I
>> do not have reliable cell service.
> 
> Xastir doesn't read .osm files directly.  You must process them into 
> shapefiles and provide a suitable ".dbfawk" file to get them rendered properly.
> Or perhaps you can download them directly as shapefiles instead.  See, for
> example:
> 
> https://wiki.openstreetmap.org/wiki/Shapefiles
> 
> 
> The "Online" directory for Xastir maps is not a collection of actual maps,
> but of special files that direct Xastir to access online tile servers.  The
> "geo" files direct Xastir to the appropriate server and directory on that
> server to which it should connect to grab tiles as it needs them.
> 
> If you're trying to download maps to use while your station is offline, such
> as while running APRS at an event, then shapefiles is the way to go.
> 
> If you're hoping to access a specific on-line tiled map set and the ones we
> already have "Online" geo files for are not adequate, then you'd have to 
> duplicate and modify one of the provided Online/*.geo files to get at the 
> particular map you want.
> 
> At the moment I use the OSM_tiled_mapnik online map for my home station and
> it is quite nice.  
> 
> If you *are* looking for offline maps and choose shapefiles, be aware that
> enormous, dense shapefiles can be very slow to render, as Xastir must read
> in the whole thing sometimes.  There is an attempt to optimize the access of
> the file using an "rtree" data structure that keeps track of which shapes in
> the file intersect the current view and only reads those in again when it
> needs to, but to reduce long-term memory usage this cache is purged when your 
> view hasn't changed in over an hour.  That is, it speeds things up if you're
> changing views a lot, but if you have an enormous shapefile and only change
> views occasionally, the first change after many hours have passed might take
> a really long time to redraw as it rebuilds the index and rtree data.
> 
> For this reason, it is often good to break enormous shapefiles up into smaller
> chunks.  There are some tools for doing that (gdal's OGR tools can help) but
> that's another story for another time.
> 
> -- 
> Tom Russo    KM5VY
> Tijeras, NM  
> 
> echo "prpv_a'rfg_cnf_har_cvcr" | sed -e 's/_/ /g' | tr [a-m][n-z] [n-z][a-m]
> 
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