[postgis] Re: How to use pgsql2shp

lr1234567 lr1234567 at yahoo.com
Thu Dec 6 14:20:30 PST 2001


Jeff,

Thanks a bunch.  Although I did not have any null geometries in my 
land parcel table, I double checked my view.  I was wrong about the 
definition of my view it was actually a left join rather than an 
inner join because and as a result did have some null geometries.

I got rid of the nulls with a where clause and that resolved the 
problem.


--- In postgis at y..., jeff lounsbury <jeffloun at r...> wrote:
> Hmmm, that error gets printed whenever there is more than a single 
geometry
> type in the result of the query so maybe you join is creating some 
rows that
> have Null geometry types and the dumped doesn't handle that very 
nicely I
> notice looking at it. Can you send me any more info you have, maybe 
a dump of
> your table possibly and I can try to look at it, but I'm pretty 
busy these
> days with other projests so I can't promise much timeliness. Feel 
free to
> poke at the code yourself, i assuming you probably just have to 
check for a
> unique geomtry OR (a unique one plus some NULL's ) bracketed is not 
happening
> in current code. Or maybe I'm completly wrong and something is 
happening due
> to the view instead of a basic table.
> -Jeff
> lr1234567 wrote:
> 
> > Jeff,
> >
> > That part I understand about the limitation of shp, but the 
geometry
> > table I was joining with only has one type of geometry
> > (multipolygons) - and that is the geometry field I am selecting 
in my
> > view.  The other table I am joining with has no geometries.
> >
> > My view query looks something like this
> >
> > SELECT ap.*, l.the_geom
> > FROM ap INNER JOIN landparcels l ON ap.parcelid = l.parcelid
> >
> > landparcels is the one with the geometry field of type 
multipolygon
> > and ap has no geometries - just a simple postgres table.
> >
> > I assumed that if I defined my new table remsactive setting the
> > geometry type the same as my landparcels, I would only have one 
type
> > of geometry.
> >
> > Note that if I try to dump out landparcels using pgsql2shp it 
works
> > fine.  Or is the fact that I am inserting from a view posing a
> > problem.
> >
> > --- In postgis at y..., jeff lounsbury <jeffloun at r...> wrote:
> > > This is simply a limitation of the .shp format. The format only
> > allows a file
> > > to consists of homogeneous shape types.
> > > eg  all Points , all MultiPolygons etc...
> > >
> > > What you can do if you really need the shapes in .shp format is
> > keep the
> > > different types in separate PostGIS tables and then dump each of
> > the tables.
> > >
> > > The other possibility is converting all the shapes to the most
> > complex type.
> > > eg. Just call points multipoints so you can have a single
> > multipoint .shp
> > > file. If the types are very different like points and 
mutipolygons,
> > this will
> > > probably not work though.
> > > -Jeff
> > >
> > > lr1234567 wrote:
> > >
> > > > Is there a particular structure that pgsql2shp is expecting
> > > >
> > > > When I try to use it on a table I created it generates the dbf
> > fine,
> > > > but can't generate the shp file
> > > >
> > > > It states as an error, can not have multiple geometry types 
in a
> > > > shape file.
> > > >
> > > > It works fine on tables I generated using the shp2pgsql 
loader.
> > > >
> > > > The way I created and populated the table I'm trying to dump 
out
> > is
> > > > as follows
> > > >
> > > > create table remsactive ( PARCELID varchar(10), ADDRESS 
varchar,
> > > > NEIGHBORHO varchar, USE varchar, TYPE varchar, STATUS varchar,
> > > > LOTAREA int);
> > > >
> > > > select AddGeometryColumn
> > > > ('dts','remsactive','the_geom','102686','MULTIPOLYGON',2);
> > > >
> > > > INSERT INTO remsactive(gid, parcelid, address, neighborho,use,
> > type,
> > > > status, lotarea, the_geom)
> > > > SELECT gid, parcelid, address,neighborhood, cuse, 
propertytype,
> > > > status, sqfeet,the_geom
> > > > FROM vwavailableparcels;
> > > >
> > > > _______
> > > > the vwavailableparcels is a view I set up that joins a table 
of
> > > > multipolygon geometries I loaded from a shape file with a non-
> > > > geometry table.
> > > >
> > > >
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