[Xastir] Xastir with offline maps

[Tom Russo]

On Sun, Jun 10, 2012 at 06:41:04PM -0700, we recorded a bogon-computron collision of the <ksaves2 at sbcglobal.net> flavor, containing:
> That was me you emailed Lee. :-)  Works fine but I found I have to move any other offline maps out of the /maps directory otherwise they get superimposed over the prior 20006 Tiger maps that I had been using.

This makes it look like you ight have "Auto Maps" turned on.  Definitely 
turn that off.

"Auto Maps" is an ancient feature of Xastir that should have been deprecated
and removed years ago (and would have but for some people who actually have a 
use case for it).  "Auto Maps" causes *ALL* maps that overlap the current 
screen area to display.  It pre-dates the parts of the map choice code that
let us pick layers, choose what zoom levels at which to display certain files,
etc.

With "Auto Maps" disabled, "Enable Map Levels" and "Enable Map Labels" turned
ON, you should be able to have as many different maps in 
/usr/local/share/xastir/maps as you care to use your disk space on, and use 
the Map Chooser to select them.

So, put your OSM shapefiles in /usr/local/share/xastir/maps/OSM, and your
TIGER shapefiles in /usr/local/share/xastir/maps/TIGER.  Reindex maps.
Then go to the Map Chooser and select only the OSM directory, don't select
TIGER.  As long as Auto Maps is turned OFF, you should get only OSM.

This is an extremely powerful way to have many maps stored, and you can
create custom maps by layering different types of data.  You can use Map 
Properties (inside the Map Chooser dialog box) to tell Xastir only to display
a given set of maps at certain zoom levels.  You can use the same dialog to
give maps a layer number so that they are on top of or below other maps ---
so you can set a raster map to layer 0, then set vector maps of various types
to higher-numbered layers.

This is how I work Xastir on search and rescue missions (no internet, never),
with USGS topo map rasters as a base layer, and assorted shapefiles layered
on top (I use county GIS department road layers, USFS trail inventory shapefiles
from the local ranger district, and assorted home-grown shapefiles).  By
choosing the maps at different zoom levels I avoid clutter --- USGS topos are
unreadable above about zoom level 59 (and not very readable then), so I don't
even bother displaying them above zoom level 59.  Some point shapefiles are
too cluttered at high zoom levels, so I only display them at low levels.  You
get the point.


> I simply moved the old TAMU tiger directory to /usr/local/share/xastir so if I want to use them again, I just swap out the OSM shapefiles to /usr/local/share/xastir and put the tiger maps back in to /usr/local/share/xastir/maps.  Works like a charm.  Perhaps there might be a way to do it from the menu-line without having the superimposition switching from one offline mapset to another.  Seems like anything in /maps is read together even if they are different mapsets.  I don't mind as the manual swapping works fine.

Really, this sounds like you're using Auto Maps.  Auto Maps is an awful feature
and should never be used unless you *really* know you want it and have something
special in mind for it.

Are the people who used to insist that Auto Maps stay in the code even still
around?  Maybe it's time to deprecate it.  I was *sure* we had already changed
the default to "OFF", but maybe we never did.


-- 
Tom Russo    KM5VY   SAR502   DM64ux          http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236        http://kevan.org/brain.cgi?DDTNM
"And, isn't sanity really just a one-trick pony anyway? I mean all you get is
 one trick, rational thinking, but when you're good and crazy, oooh, oooh,
 oooh, the sky is the limit!"  --- The Tick