[Xastir] Xastir with offline maps

[Tom Russo]

On Mon, Jun 11, 2012 at 10:18:52PM -0600, we recorded a bogon-computron collision of the <russo at bogodyn.org> flavor, containing:
> On Mon, Jun 11, 2012 at 09:58:48PM -0400, we recorded a bogon-computron collision of the <n1mjf at n1mjf.com> flavor, containing:
> > I'm sure there is some conversion I have to do with the .dbf files. I tried
> > renaming them to .dbfawk, I did get some result from that but it made it
> > way worse and complained about too many rows or something. I will keep
> > digging.
> 
> No, renaming the dbf files to dbfawk is very much the wrong thing to do.
> 
> What you need to do is make sure that your Xastir is built with pcre 
> and dbfawk.  Please post the last block of lines that "configure" prints,
> where it has all the features listed and whether they're enabled or not.  
> dbfawk is an internal feature of Xastir, pcre is an external library you 
> need to have on your system with its development headers when you configure
> Xastir.
> 
> Shapefiles look like crap without dbfawk, except for a small handful of
> extremely outdated shapefiles that have hard-coded support.

FWIW, this wiki page describes dbfawk usage in some detail:

http://www.xastir.org/wiki/HowTo:DBFAWK

This is more information than necessary to get the cloudmade OSM shapefiles
working, though.  You don't actually have to do anything with dbfawk to use 
the cloudmade OSM shapefiles, because Xastir already comes with dbfawk files 
for those shapefiles that are designed to get the display as close as possible 
to the on-line versions (which isn't very close --- mapnik is an 
extraordinarily high quality map renderer, and Xastir is just good enough to be 
useful).

One of the reasons your rendering is so slow (other than running on a slow
machine) is probably that without dbfawk, it is likely that all the lines in 
all the files are being drawn at all zoom levels, and none skipped over.  
Also, make sure you have "rtree" enabled (it is by default) which can speed up 
re-rendering of shapefile maps by keeping a spatial index of features and 
allowing faster determination of which ones are on screen. Without rtree, 
Xastir does a linear search through every shapefile, testing every feature for 
whether it's on screen or not, every single time the shapefile is rendered.  
With huge shapefiles, this can be prohibitively slow, especially when zoomed 
in so close that only a fraction of the features in the file are on screen.

-- 
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