That worked great, Tom! Thanks.... I used the symlinks to generate
three "zoom level ranges" and each range had its own dbfawk.
Using the Station Symbol function in Xastir, I got the symbol code that
I wanted, but is there a table somewhere that lists the TIO codes and
the associated image?
Thanks again.............. jt
Tom Russo wrote:
On Thu, Oct 23, 2008 at 04:24:26PM -0500, we recorded a bogon-computron collision of
the <[EMAIL PROTECTED]> flavor, containing:
What is the best way to go if I want the points in a shapefile to be
represented by one symbol for one range of zoom values and another
symbol for a different range of zoom values.....that is symbol=\l (
small dot) on higher zooms and symbol=/- (little house) on lower zooms,
for example.
Do I duplicate the all of the shapefile files to a new name and then
have two dbfawk files... one for each zoom range? Is there a way to
only have two dbfawk files or two expression lines in the same dbfawk file?
At this time, I do not believe it's possible to have a single DBFAWK do
this. You will have to do the duplicate thing. Messy, but the way it is.
The obvious thing to try won't work: putting multiple rules for a given
match.
When a match is found in a dbfawk file for a given record, that match causes
certain variables to be set, for example:
/^SOMEFIELD=(.*)$/ {name="$1"; display_level=256; symbol="/. ";}
Every time "SOMEFIELD" is found the value is set as the name and the symbol
is set. This rule restricts view of this item to zoom levels below 256.
If you were to try to accomplish what you want by having a second matching
rule:
/^SOMEFIELD=(.*)$/ {name="$1"; display_level=256; symbol="/. ";}
/^SOMEFIELD=(.*)$/ {name="$1"; display_level=512; symbol="/! ";}
then all that would happen is the second rule would win, always.
So at this point, the only way to accomplish what you want is to have two
copies of the shapefile (or a symlink) and two dbfawk files, and restrict
which one is read using the Map Properties min/max zoom options.
The easy way to do that is with a symlink:
ln -s mymap.shp mymap_fake.shp
ln -s mymap.dbf mymap_fake.dbf
ln -s mymap.shx mymap_fake.shx
and have a mymap.dbfawk and mymap_fake.dbfawk. Set mymap to be displayed at
one range of zoom levels and mymap_fake to another, then set the dbfawks
to set the symbology as desired.
Complex map rendering isn't really in Xastir's capabilities. We already have
more than many GIS systems do, in that we can prune features by zoom levels
and label them with wild combinations of attribute values, but we can't do it
all.
--
Jim Tolbert
[EMAIL PROTECTED]
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