[Xastir] Customized Maps in Xastir (Questions from Mykle)

[Curt, WE7U]

We were discussing this on the SAR-APRS list a few weeks back and I
suggested moving the discussion onto the Xastir list as it was
getting quite Xastir-specific and somewhat detailed.  Perhaps some
of our map experts can help answer the specific questions for Mykle?

Below are the original discussions.  Please answer what you can so
that the answers are in our archives & searchable.  Thanks!  --we7u

----

From: Mykle Raymond
Subject: Re: [SAR_APRS] Hello all

wolf184 wrote:
> Dmapper can be used with delorme topo without UI-view at all. So that is
> a nice but many stepped process with no real time update. So this brings
> my next question. I went to USGS and all I can find to get for topo maps
> from there is the .pdf files. Am I missing the geotiff section and are
> they free?

http://libremap.org

Caveat: While the list of states is complete, at least
one of them (Alaska) does not list any map files.

That said, there are usually other sites that provide
maps of limited areas (like those of Alaska), or that
may provide maps that libremap does not.  I know a few
of them, and many provide files without cost to you.

Again using Alaska as an example, the common topo map
scale is 1:63,360 (similar to the old 1:62,500 for CONUS),
and a few maps are available at 1:25,000 (similar to the
current 1:24,000 for CONUS).

Those groups that have the services of people with GIS
tools can create maps of specific areas of interest, using
stock USGS DRG files, and include updated roads, trails,
and other features.  This is a major advantage over topo
map display programs that are usually limited to the
original map editions.  This is an improvement upon reloading
a pile of track and waypoint files.

Your group may use a legacy map that doesn't exist in
digital form, for example.  If it uses a consistent scale,
it can usually be scanned and georeferenced for display in
GIS programs.  I use Photoshop, GIMP, and Global Mapper.

Curt: can custom maps be used in Xastir?  I recall that
some assumptions were originally made to use USGS DRG,
especially since most of them are NAD27 and APRS uses
NAD83/WGS84.  I haven't tried (yet) to load any of my
custom maps into Xastir.  I use them in Oziexplorer
without problems.

Cheers,
Mykle Raymond
Southern Arizona Rescue Association
Tucson

----------------------------------------------

On Tue, 11 Aug 2009, Mykle Raymond wrote:

> Curt: can custom maps be used in Xastir?

We can handle darned-near any image map format, but if they're DOQQ
or DRG geoTIFF images then Xastir needs formats that are just like
the USGS versions.


> I recall that
> some assumptions were originally made to use USGS DRG,
> especially since most of them are NAD27 and APRS uses
> NAD83/WGS84.

Blame me for those assumptions...  hi hi  --we7u

---------------------------------------------

The debbil is in the DEEtails ...

All of the special maps that I have been creating have used UTM
projection.  All are GeoTIFF, and include a TFW global file.
Some may use NAD27, and some NAD83.  Otherwise, while the boundaries
are defined by UTM eastings and northings, these maps have not been
created to any standard like DRG boundaries at a regular 7.5'
interval.
The coverage has been designed for particular areas of interest
so we don't have to be flipping maps (much).

Our Ubuntu box has a reasonable internet connection, so I have
just been using on-line maps.  At some point, I'll need to use
our DRG collection, and I'll be interested in loading the custom
maps and am curious about how successful that might be.

In the trucks, I'm still using Windoze computers with UI-View
providing a port for OziAPRS to grab the packet stream and feed
it to OziExplorer (which displays the custom maps without problems).
The UI-View shows wide-area street maps as an overview, and Ozi
shows the detailed topo maps.  We are not saturated with 144.39
traffic, so we get to use the established network of high and
low level digipeaters to complement the SAR-specific digis in
several vehicles.

Mykle

-------------------------------

This is getting into application-specific details best done on an
application-specific mailing list instead of a general SAR-APRS list
like this one.  The Xastir list would be better.  Probably Tom R.
and I could answer your questions fully there, plus other Xastir
users might benefit from the discussion too.  This level of detail
makes everybody else too glossy-eyed.  --we7u