Parametric Objects

Parametric objects refer to geometries that use one or more parameters (such as angle, length, etc.) to represent (x, y) coordinate points. For example, circles and ellipses are expressed using parametric equations:

Circle: x=a+rcosθ, y=b+rsinθ (θϵ[0,2π))
Ellipse: x=acosθ, y=bsinθ (θϵ[0,2π))

The benefit of using parametric objects to express the geometric features of ground objects is that when the contour lines of real-world ground objects contain curves, using parameterized data for description makes the map display fit the actual object contours more closely and improves accuracy in geometric calculations such as area and perimeter.
Figure Contour curve of a playground

Parametric Objects Types

Currently, parametric objects supported for storage in line and region datasets include circles, arcs, ellipses, elliptic arcs, 3rd-order Poly Bezier, as well as compound lines and compound region datasets composed of these parametric objects. Specific parametric object types are described below:

Parametric Objects
Description
Parametric Objects Graphic
Class Name
Arc
 
GeoArc
Circle
 
GeoCircle
Elliptic Arc
 
GeoEllipticArc
Ellipse
 
GeoEllipse
Poly Bezier
3rd-order Poly Bezier
GeoBezier3Curve
Parametric Line
Can be composed of the following geometries: polyline (GeoLine), arc (GeoArc), circle (GeoCircle), elliptic arc (GeoEllipticArc), ellipse (GeoEllipse), poly bezier (GeoBezier3Curve), and the end coordinate of the previous geometry coincides with the start coordinate of the next geometry.
GeoCompoundCurve
Parametric Region
Can be composed of the following geometries: polyline (GeoLine), parametric line (GeoCompoundCurve), circle (GeoCircle), ellipse (GeoEllipse), and all geometries are closed.
GeoCurvePolygon
Parametric Multi-curve
Composed of multiple sub-objects. Each sub-object contains only one geometry, which can be: polyline (GeoLine), arc (GeoArc), circle (GeoCircle), elliptic arc (GeoEllipticArc), ellipse (GeoEllipse), parametric line (GeoCompoundCurve), poly bezier (GeoBezier3Curve). Specifically, when the sub-object is GeoLine, the contained line object count can only be 1.
GeoMultiCurve
Parametric Multi-surface
Composed of multiple sub-objects. Each sub-object contains only one geometry, which can be: region (GeoRegion), parametric region (GeoCurvePolygon). Specifically, when the sub-object is GeoRegion, the contained region object count can only be 1.
GeoMultiSurface

Import Parametric Objects from External Formats

Currently, importing parametric objects from DWG and FileGDB data is supported, and it is supported in Windows_x86, Linux_x86, and Linux_arm environments.

  • DWG
    DWG Geometry
    Import as Line/Region Dataset
    Import as CAD Dataset
    Keep Parametric Object
    Do Not Keep Parametric Object
    Keep Parametric Object
    Do Not Keep Parametric Object
    Circle, Ellipse
    Circle, Ellipse
    Fitted Polyline/Fitted Region
    Circle, Ellipse
    Circle, Ellipse
    Arc, Elliptic Arc
    Arc, Elliptic Arc
    Fitted Polyline
    Arc, Elliptic Arc
    Arc, Elliptic Arc
    Spline Curve
    Parametric Line
    Fitted Polyline
    Parametric Line
    Fitted Polyline
    Polyline
    Parametric Line
    Fitted Polyline
    Parametric Line
    Compound
    Hatch Pattern
    Parametric Region
    Fitted Region
    Parametric Region
    Compound
    Block
    Parametric Line/Region
    Fitted Polyline/Region
    Parametric Line/Region
    Compound

    * When importing a Polyline as a CAD Dataset, you need to set "Keep Parametric Object", and it must meet the condition of containing parametric objects and ignore polyline width or have polyline width of 0 to be imported as parametric objects; otherwise, it will be imported as a compound.

    * Importing DWG as parametric objects only supports importing as two-dimensional datasets. If you want to keep object height information, it will be fitted as a polyline.

  • FileGDB
    FileGDB Geometry
    Import Line/Region Dataset
    Circle, Arc
    Circle, Arc
    Poly Bezier
    Parametric Multi-curve, sub-object is Poly Bezier
    Circle, Ellipse, Parametric Region
    Circle, Ellipse, Parametric Region
    Line/Region feature composed of multiple lines/regions (see Figure 2)
    Parametric Multi-curve/Parametric Multi-surface

    * When a line/region feature in FileGDB contains multiple sub-objects (as shown in the figure below), it will be converted into a Parametric Multi-curve/Parametric Multi-surface containing multiple sub-objects upon import.

    Figure Parametric Multi-curve composed of multiple sub-objects
  • Other External Formats

    Parametric objects from other external formats will be fitted into polylines upon import.

Export Parametric Objects to External Formats

The current platform supports exporting parametric objects to multiple data formats, including: DWG, DXF, FileGDB.

  • FileGDB export support: Currently only supports exporting two types of parametric objects: circles and arcs.
  • DWG, DXF export support: Exporting parametric objects is supported in Windows_x86, Linux_x86, and Linux_arm environments.
  • Other format export notes: Parametric objects exported to other formats will automatically be fitted as polylines.

Currently, only when exporting parametric objects to DWG or DXF format can they remain as parameterized objects, and this is supported in Windows_x86, Linux_x86, and Linux_arm environments. Exporting to other formats, including those that do not support parametric objects such as CSV, GeoJSON, KML, etc., will cause parametric objects to be fitted into polylines.

Function Support Status

  • Currently supported vector processing and analysis functions for parametric objects include: overlay analysis, buffer analysis, merge, regularization of buildings, calculate the area, vector resampling, double-line extraction centerline, faces extract centerlines, distance calculation, line and surface smoothing, create random point, vector rasterization, attribute update, sheet edge, vector clipping, line topology processing, shard polygons merge, polygon dissolve, clustering and outlier analysis, hotspot analysis, etc.
  • Starting from the SuperMap iDesktopX 2025 version, the feature editing functions supported for parametric objects only include: erase, line to point, region to line, line to region, specify coordinates, specify orientation, specify offset, positioning copy, mirror, rotate.

Related Topics

Objects Overview