[Xastir] maps

[Tom Russo]

On Wed, Feb 25, 2004 at 12:13:41AM -0600, a Mr. Richard Feyler of Fort Lee, New Jersey <tbaggett at jump.net> writes 'Dear Rosanne Rosannadanna':
> 
> > Ask specific questions on this list, perhaps 1 to 3 questions per
> > e-mail.  Multiple people will get a chance to attempt answers that
> > can be understood at the 101 level.  Everyone will benefit from the
> > threads that ensue.
> 
> 
> Okay, not seeing any questions specificly in reply to Curt's offer, I'll
> start :-)
> 
> 1) What is the maximum number of maps (# files and file sizes) that people
> have realistically used with Xastir?

I have 33 shapefiles converted from tiger data (I did it that way, because
the tiger data was more conveniently downloaded than the esri.com files,
which were not organized to my liking).  That covers all counties in 
New Mexico.  They are anywhere from 2-13MB each.  I rarely have the program
zoomed out to cover the whole state, and I use agressive map levels to keep
render time short.  Even so, it is slow to display the entire state.

I also have about 200 USGS topo maps (covering most of central New Mexico
in 1:24000, 1:100000, and 1:250000 scale).  I also use some fairly agressive
level settings on those, so that only a few of the 1:24000 maps are ever
visible, since they're illegible at high soom levels anyway.  I used to 
have it set up to show the 1:25000 scale at high zoom levels, then the 1:100000
scale at middling zoom levels, and 1:24000 at low zoom level.  I found the
switch from the various scales to be distracting, and at high zoom levels
the screen was just too busy, so now I only render line data at high zoom.
These files are around 8MB each.

I've got a dozen or so miscellaneous shapefiles ranging from 75K to 2MB, and 
some GNIS files ranging from 2MB to 6MB.  

Setting map levels appropriately, you can get away with a huge number of 
maps, and just not render them all at any particular zoom level.

On average, my screen will contain from 5 to 30 shapefiles depending on zoom, 
and no more than 6 USGS topos at any zoom (usually either 0 or 2).

> By the way, in response to my previous email last week, GIS Tools' TGR2SHP
> utility seems to generate shapefiles that are no problem with Xastir.
> However, there must be some difference with them, as the dbfawk scripts that
> come with Xastir don't seem to take effect on the converted shapefiles as
> they do on shapefiles downloaded from ESRI's web site.

Your dbf signatures are probably different than the ESRI files.

I used ogr2ogr to generate my shapefiles.  All I had to do to make a dbfawk
script that worked was to copy tgrlk.dbfawk and change the DBFINFO
line so the signature matched what ogr2ogr generated in the shapefile.
While I was at it I tinkered with the display properties in my copy.
The "testawk" program that gets built when you build xastir (but never 
installed) was very helpful for that.

-- 
Tom Russo    KM5VY     SAR502  DM64ux         http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236 AHTB#1 http://www.qsl.net/~km5vy/
 "It is inhumane in my opinion to force people who have a genuine
  medical need for coffee to wait in line behind people who apparently
  view it as some kind of recreational activity."  -- Dave Barry