Thanks all for the replies. 

>From my own searches today I found the following, which may be of
interest to those who stumble on this thread in the future.CIRCULARSTRINGs are 
supported in MapServer for PostGIS, as described in
the docs at
https://mapserver.org/input/vector/postgis.html#example-1-circularstring-in-mapserver
Looking at the code it creates lines from the curves, similar to the OGR
function Even pointed out:
https://github.com/mapserver/mapserver/blob/636394c7e205ec6bdb9d8c3beb8edb45a39722c0/mappostgis.c#L547
As GEOS is a port of the JTS, then it seems as though curves will never
be supported. From
http://docs.geotools.org/stable/userguide/library/jts/geometry.html -
*The JTS Topology Suite does not have any constructs to represent a
“curve” or “circle” - GeoTools added that as an extension. The
mathematics used by JTS is strictly limited to geometry made up of
straight (i.e. linear) lines.The GeoTools curve implementations rely on
using control points to define a curve, and converting it to a straight
lines at the last possible moment. *
I can add a note on this to the docs at
https://mapserver.org/mapfile/feature.html. For WKT it states *"**This
feature is only supported if MapServer is built with OGR or GEOS
support" - *is there any way of forcing the use of OGR rather than GEOS
for curves? Is there such as thing as an OGR WKT layer?
Related RFC and implementation details at:
https://www.mapserver.org/fr/development/rfc/ms-rfc-2.html
https://github.com/mapserver/mapserver/issues/1466

Regards,

Seth

--
web:http://geographika.co.uk
twitter: @geographika


On Fri, Sep 7, 2018, at 4:30 PM, Basques, Bob (CI-StPaul) wrote:
> All, 
> 
> We moved to storing curves in Postgres/postgis as a way of
> distributing to those applications/clients that can consume curves.> 
> The Postgres loading stuff has been somewhat manually intensive in
> setting up, but it’s somewhat automated now.  We’re sourcing data from
> both AutoCAD and ESRI Features, and converting to CircularStrings in
> postgres.> 
> bobb
> 
>  
> 
> 
>> On Sep 7, 2018, at 7:54 AM, Even Rouault
>> <even.roua...@spatialys.com> wrote:>> 
>> On vendredi 7 septembre 2018 12:42:08 CEST Lime, Steve D
>> (MNIT) wrote:>> 
>>> I'm pretty certain it's a no... I would think it should be
>>> possible to>>>  marshall curves into MapServer shapes though. --Steve
>> 
>> OGR has infrastructure to convert from curve geometries to
>> approximated curve>>  geometries with
>> 
>>  geom = OGR_G_ForceTo(geom,
>>    OGR_GT_GetLinear(OGR_G_GetGeometryType(geom)), NULL)
>> 
>>  as used in mapogr.cpp for example
>> 
>>  -- 
>>  Spatialys - Geospatial professional services
>> http://www.spatialys.com
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> 
> 
> "The difference between stupidity and genius is that genius has its
> limits.”> -  Albert Einstein
> 
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