Export to DXF from Multipoint Z geometry in PostgreSQL using ogr2ogr

Question

I want to export a PostgreSQL table of geometries in Multipoint Z to DXF using ogr2ogr

I tried this command

ogr2ogr -f "DXF" output.dxf PG:"host='127.0.0.1' port='5432' \
dbname='dbname' user='user' password='password'" -sql \
"select st_transform(st_geomfromewkb(decode(geometry_base64, 'base64')), 4326) as geom \
from my_table limit 1"

but get errors:

ERROR 1: No known way to write feature with geometry 'Multi Point'.
ERROR 1: Unable to write feature 0 from layer sql_statement.

ERROR 1: Terminating translation prematurely after failed
translation from sql statement.

Answer 1

DXF format does not really support multipoint geometry type and therefore GDAL DXF driver https://gdal.org/drivers/vector/dxf.html can't handle them. FME does support multipoints with a workaround by storing them as blocks https://docs.safe.com/fme/2018.1/html/FME_Desktop_Documentation/FME_ReadersWriters/acad/Geometry-Support-acad.htm

What you can do with ogr2ogr is to explode multipoints into simple points https://gdal.org/programs/ogr2ogr.html

-explodecollections

Produce one feature for each geometry in any kind of geometry collection in the source file

Proof of concept:

ogr2ogr -f dxf multi.dxf multipoint.jml 
ERROR 1: No known way to write feature with geometry 'Multi Point'.
ERROR 1: Unable to write feature 0 from layer multipoint.
ERROR 1: Terminating translation prematurely after failed translation of layer multipoint (use -skipfailures to skip errors)

ogr2ogr -f dxf multi.dxf multipoint.jml -explodecollections

Conversion succeeds, now check the result:

ogrinfo multi.dxf entities
INFO: Open of `multi.dxf'
      using driver `DXF' successful.

Layer name: entities
Geometry: Unknown (any)
Feature Count: 3
Extent: (500.000000, 360.000000) - (590.000000, 454.000000)
Layer SRS WKT:
(unknown)
Layer: String (0.0)
PaperSpace: Integer(Boolean) (0.0)
SubClasses: String (0.0)
Linetype: String (0.0)
EntityHandle: String (0.0)
Text: String (0.0)
OGRFeature(entities):0
  Layer (String) = 0
  SubClasses (String) = AcDbEntity:AcDbPoint
  EntityHandle (String) = 20000
  Style = PEN(c:#000000)
  POINT Z (590 454 1)

OGRFeature(entities):1
  Layer (String) = 0
  SubClasses (String) = AcDbEntity:AcDbPoint
  EntityHandle (String) = 20001
  Style = PEN(c:#000000)
  POINT Z (513 411 2)

OGRFeature(entities):2
  Layer (String) = 0
  SubClasses (String) = AcDbEntity:AcDbPoint
  EntityHandle (String) = 20002
  Style = PEN(c:#000000)
  POINT Z (500 360 3)