[Opencities Map] Interoperability: Keep 2D curves and arcs on GIS data export

Looking for a solution which database to use so 2D DGN data can be exported to GIS spatial database but with keeping curves and arc elements so are easy editable(not stroked) after query from database.

This is needed for land surveying workflow with multiple surveyors working in one large area but different places. As multiple users cannot open the same design file at the same time they are struggling with updating data in same large DGN wich contain all Project area it would be better that features are stored in a spatial database, each user will work in their own individual design files but at the end of the day promote the changes to database.

Does Oracle Spatial or ESRI GDB support this?

  • Hi Oto,

    my experience is that "curves" are typically not supported. But for any more specific discussion: What types of "curves" are you interested in? MicroStation supports curve, B-spline curve, Bezier curve...

    With regards,


  • Most simple ones Point Curves and B-spline curves(open or closed, trough point only).

    I read in documentation that:

    NURBS support is in Oracle 12C and later. OpenCities Map will support the new NURBs (Non Uniform Rational B-spline) data type in Oracle Spatial. Oracle supports these curves in 2D only with a projected coordinate system. These are supported as SDO_GTYPE=2006

    What has changed from past years in this paragraph is only Bentley Map replaced with OpenCities Map.

    Also there is such comparison between XFM features and Oracle.

    NURBS d/2006 2D only with projected coordinate system. Supports a curve with one NURBS curve element and no other elements - no support at this time for compound line string containing NURBS curve elements.

    I have a feeling that all this is snake oil and no real support exists. Oracle 12c was released like in year 2013.

  • For ArcGIS I read this in their documentation:

    • Write circular curves to the SDO_GEOMETRY type when the feature class is registered with the CAD entity mask (c); otherwise, convert the curves to densified straight-edged linestrings.

    • Convert noncircular arcs (cubic spline, Bezier) to straight-edged linestrings. When the feature class is registered with the CAD entity mask (c), also store the curved representation in SE_ANNO_CAD_DATA.

    Prior to ArcGIS 10.3.1, curves in a PostgreSQL geometry feature class are stored as densified lines (not curves). The implementation of the GDB_GEOMATTR_DATA column makes the ArcGIS feature classes stored in PostgreSQL geodatabase consistent with Oracle and SQL Server native spatial types, which apply the same concept in a similar fashion.

    Seems I'm screwed and there is no solution in Bentley platform.

  • This ultimately depends on the actual spatial database you intend to use. I'm almost sure we support circular arcs at least in Oracle, if the database is of the right version and configuration. Let me ask the support team here...


  • Please find out as "will support" doesn't sound too promising. The intended database depends of support for such features but of course it would be preffered to avoid Oracle products in this case.

    I also contacted local ESRI support to clarify but they are also puzzled as for their purposes segmented curves to lines are ok.