[Xastir] Vector Formats.

[Curt, WE7U]

On Mon, 28 Jan 2008, Jason KG4WSV wrote:

> On Jan 25, 2008 3:15 PM, John Ronan <jronan at tssg.org> wrote:
>
> > Someone new to APRS in Ireland with access to mapping data has asked
> > me "If" I had a choice of formats, what would I be looking for.  Now
> > I'm fairly sure that 'shapfile' is the answer, but I know that its
> > not as simple as that.  What would be the 'correct' answer, or could
> > someone point me at an 'ideal' map?
>
> shapefile certainly seems the most flexible to me, given the dbfawk
> capability we currently have.  As far as I know, the other vector formats
> supported by xastir do not have capability to change features (color, line
> style, etc), or have hard coded support.

Pretty much.  The downside to Shapefiles though is that you
sometimes need to run them through processing to change units,
change datums, etc, before some programs like Xastir can use them.
There's also no standard "attributes" file that goes along with
shapefiles:  Colors, line-widths, etc, _may_ be specified in the
dbf file, but may not.  Also, the format of the dbf file is not
standard (which things are in which columns, the names of columns,
etc).

Shapefiles can be very fast to read in or reject, as they have a
bounding box for the entire file, and a bounding box for each shape.
You can quickly look at a file and reject it if no part of the
bounding box is viewable on the current screen.

--
Curt, WE7U: <www.eskimo.com/~archer/>     XASTIR: <www.xastir.org>
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