Re: spatialite 4
Hi Francesco,
2014-04-06 18:05 GMT+02:00 Francesco P. Lovergine <frankie@debian.org>:
[...]
> The null vs -1 vs 0 value for undefined SRID is a disputed issue.
> For sure having no SRID has no sense for so many functions that
> I should ask you what is the reason to do that, but for temporary
> data injections.
In fact, I'm using spatialite to interpret soil analysis data, and in
particular texture [1].
I'm creating a temporary in-memory database reproducing the GEPPA
texture triangle, to find which texture applies to my sample.
I then create two polygons for the optimal areas for truffle species,
to see if my soil sample is suitable.
So, using spatialite for this is a little like using a car to crush a
mosquito, but it's really easy to set up (python script to query datas
in Oracle database and to interpret texture, LibreOffice datasheet to
print a report for the customer).
That's why I didn't specified a SRID, as my coordinates where just x-y
(50 % clay and 32 % loam for exemple).
Re-reading the postgis tutorial I used to create my database, I see
that even with that type of coordinates they specify the SRID in
GeometryFromText() : I overlooked this detail.
Anyway, now I am aware of this issue, and I'll specify the SRID in my queries.
Sébastien
[1] http://julienmoeys.free.fr/DB/phpwebgallery/picture.php?/1476/category/92
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