Following on from my last basic query:
(I'm updating my data based on new sets of shapefiles - but I'm not
from an ESRI Arc background, so I don't know much about how it might
work.)
I notice that Shapefiles often have in their associated .dbf file
information about the GIS objects (not just the real world item it is
meant to represent), ie a file of roads might have the name of the
road, the category (ie A, B or C road), the number of lanes etc. And
it also has a number of other columns :
fnode, tnode?
I gather these are for line direction - Isn't this stored in the line
definition in PostGIS? (I note Surya's questions from yesterday - I
need to be able to route in the system)
rpoly, lpoly? I have no idea what these are for - How does a left or
right polygon information help? - should I keep them ?
length - Is it necessary, or am I better to calculate it on the fly
using postgis functions?
(area for some data)
ultimately, would keeping them be helpful, or would discarding them be
prudent to shrink the table, and the information that they provide can
be calculated if / when I need it?
cheers
Ben
--
Ben Madin
REMOTE INFORMATION
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Broome WA 6725
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Out here, it pays to
know...
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