> Some geoprocessing activities that are easy to do in ArcInfo are
more-or-less as easy to do in PostGIS.
That caused another question I have regarding PostGIS: Is there any
documentation around to help ArcGIS users learn PostGIS (and probably vice
versa)? I'm thinkin about a listing or table simil
Well, for sparse vs non-sparse, Martin's still-dreamy
PreparedIntersection() enhancement might actually make a good effect.
P
On Thu, Jan 29, 2009 at 5:44 PM, Chris Hermansen
wrote:
> I too would hope for someone to spend some quality time on this
> problem. Here are a few other related thought
I too would hope for someone to spend some quality time on this
problem. Here are a few other related thoughts:
* GOAI (that's Good Old ArcInfo, you know the one with AML, not the
one that only runs on that funny O/S from WA) has pretty archaic
geoprocessing stuff built in, genera
Chris, generally I agree (especially if the code is written in Java...
8^). After I posted this I started thinking that probably a few more
minutes/hours/days splunging through the C code would no doubt reveal
much about how it actually works. At the moment however I can't even
tell if it is
Martin, Martin, Martin: code is the best documentation there is! and
besides, it's not written in Perl so how bad can it be :-)
Martin Davis wrote:
> Have you looked at the code? I rest my case
>
> Paul Ramsey wrote:
>> On Thu, Jan 29, 2009 at 8:42 AM, Martin Davis
>> wrote:
>>
>>> The ba
Have you looked at the code? I rest my case
Paul Ramsey wrote:
On Thu, Jan 29, 2009 at 8:42 AM, Martin Davis wrote:
The basic approach to computing polygon overlays has been well-understood
for a long time (although this does not imply well-documented!). The
implementation however is
On Thu, Jan 29, 2009 at 8:42 AM, Martin Davis wrote:
> The basic approach to computing polygon overlays has been well-understood
> for a long time (although this does not imply well-documented!). The
> implementation however is quite tricky, especially if performance and
> robustness is required.
The big problem with this in PostGIS land is that Union (or let's call
it Overlay, to distinguish it from the existing Union) is a *global*
function. I.e. it operates over *all* polygons in a table (or set of
tables). This is in contrast to most existing PostGIS functions, which
operate over
Following on from Paul's note about a function that would make the
output of st_intersection() more immediately useful, I have a favourite
whine to mention.
Some geoprocessing activities that are easy to do in ArcInfo are
more-or-less as easy to do in PostGIS. One, though, seems to me to be
