Issues geometry constraints

[kk mensah]

HI All,

I am facing a brick wall and need some assistance.

I am using spalialite_gui and running a small project on motorways, my issue is with a timy part of my code.

CREATE TABLE motorway_buffers(

                id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,

                mortorway_number TEXT NOT NULL,

                buffer_name TEXT NOT NULL)

 

SELECT AddGeometryColumn('motorway_buffers', 'geometry', 27700, 'MULTIPOLYGON', 'XY')

 

INSERT INTO motorway_buffers

                (id, mortorway_number, buffer_name, geometry)

SELECT NULL, number, 'buffers < 1km',

                CastToMultipolygon(ST_Buffer(geometry, 1000.0))        

FROM motorway

The area highlighted are gives an error saying : 

SQL error: motorway_buffers.geometry violated geometry constraint [geom-type or SRID not allowed]

kindly help break through this wall. Thanks

[andrea antonello]

Hi Mensah,

From your query I do not see where the geometry comes from, but when
you create it, you need to do it supplying the srid. I guess the
geometry you are inserting doesn't have it defined, hence the
violation.

Ciao,
Andrea

>
>
> kindly help break through this wall. Thanks
>

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[mj10777]

The geometry must be (at least) a POLYGON and have the srid 27700 (which you defined) 

Mark

[kk mensah]

Thanks MJ,

the code looks ok but cant seem to find what it is im missing. Any suggestions?

[kk mensah]

Thanks Moovida,

I am still working on it. Nothing seem to work though

[a.fu...@lqt.it]

On Sat, 12 May 2018 06:27:23 -0700 (PDT), kk mensah wrote:
> SQL error: motorway_buffers.geometry violated geometry constraint
> [geom-type or SRID not allowed]
>

Hi,

rule number zero: always carefully check your data so to
discover what is causing troubles.
you've created the destination geometry column as:

SELECT AddGeometryColumn('motorway_buffers', 'geometry',

27700, 'MULTIPOLYGON', 'XY');

and consequently the possible causes for a constraint
violation are the followings:

1. any GeometryType different from MULTIPOLYGON
2. any SRID different from 27700
3. any Dimension different from XY

now, your first check should be to carefully verify
which values is actually returning your SQL query;
and in order do to this you just have to execute a
rather trivial diagnostic query such as:

SELECT GeometryType(g.g) AS type, Srid(g.g) AS srid,
CoordDimension(g.g) AS dims, Count(*) AS count
FROM
(
SELECT CastToMultiPolygon(ST_Buffer(geometry, 1000.0)) AS g
FROM motorway
) AS g
GROUP BY type, srid, dims;

after performing this very basic check you'll be probably
able to resolve the problem by yourself.
if not, you can eventually post a new message by specifying
your actual findings and asking for further help.

bye Sandro

[kk mensah]

Wow Thanks Sandro,

The query returned srid as 0, hence the error. Now to fix that.

thanks again