I am looking for the function to use to create linestring geoms from
existing point geoms. I am aware of all of the functions for creating
line from WKB or WKT, so I just assumed that there are functions do do
this directly from point geoms.
I am sure that I can just flop them from geoms to WKB using AsBinary()
and then use LineFromWKB() to build new linestring geoms, but this
seems a little inefficient.
Are there functions to do this directly with Spatialite point geoms?
Thanks,
David.
Hi David,
I'm really sorry, but OGC-SFS has absolutely
nothing like this
A little bit of not-sql code is absolutely
required to perform such task (C, python ...)
bye Sandro
Thanks Sandro!
David.
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This has been on my wishlist for quite some time in general for FOSSGIS.
http://www.qgis.org/wiki/Google_Summer_of_Code_2010#Basic_Vector_Conversions.2C_Manipulations
Take a look at the Points2One plugin in QGIS which is intended for
Points to Polygon but could probably be hijacked.
I also know at least 2 people who have R code that does this and I'll
try to get a copy.
Down the road aggregation functions in SQL would be awesome, but I think
we'll need a c coder to step in and set that up.
Thanks,
Alex
I know that this functionality also exists in PostGIS in
ST_MakeLine(). I don't know if it is based on Postgres functionality
that doesn't exist in Sqlite.
http://postgis.org/documentation/manual-1.5SVN/ST_MakeLine.html
I hesitate to even mention this because somewhere in the back of my
head, I imagine Sandro skipping his sleep tonight and implementing
it...
David.
Hi David,
> I hesitate to even mention this because somewhere in the back of my
> head, I imagine Sandro skipping his sleep tonight and implementing
> it...
>
Do you see ? it's definitively confirmed,
you are a sorcerer :-)
anyway, you are only half-way right:
a) yes, I actually skipped (part of) my sleep tonight
b) but not at all because I was working on ST_MakeLine
I'm currently deeply busy with TopoGML 3.1.1 parsing
[optimizing huge GML file processing: > 2GB] :-)
seriously speaking: really a good suggestion.
the next release will support ST_MakeLine for
sure (and it seems quite easy to be implemented).
bye Sandro
Excellent work Sandro!
David.