Parametric objects

Parametric object refers to a Geometry that uses one or more parameters (such as angle, length, etc.) to represent (X, y) coordinate points. For example, a circle or ellipse is expressed by a parametric equation as:

Circle: X = a + rcos rcos, y = B + rsin rsin (ɵ 0,2))
Ellipse: X = acos acos, y = bsin bsin (ɵ 0,2))

The advantage of using parametric objects to express the geometric characteristics of ground objects is that when there is a curve in the contour line of ground objects in reality, parametric data is used to describe it, which is more suitable for the actual contour line of ground objects in map display and more accurate in geometric calculation such as area and perimeter.

Fig. 1 Profile Curve of Playground

Parameterized Object Type

The parametric objects supported to be stored in the current line and Region Dataset include circle, arc, ellipse, elliptical arc and Poly Bezier of order 3, and the composite line and Region Dataset composed of these parametric objects are also supported. The specific parameterized Object Type is described as follows:

Parametric Object
Description
Parametric Object Graphics
Class Name
Arc
 
GeoArc
Circle
 
GeoCircle
Elliptic arc
 
GeoEllipticArc
Ellipse
 
GeoEllipse
Poly Bezier
 Poly Bezier of order
3
GeoBezier3Curve
Parametric Line
 Geometry
can be composed of: 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.
GeoCompoundCurv
Parametric Region
It can be composed of the following Geometry: Polyline (GeoLine), Parametric Line (GeoCompoundCurve), Circle (GeoCircle), Ellipse (GeoEllipse), and each Geometry is closed.
GeoCurvePolygon
Parametric multiline
Consists of multiple sub-objects, each of which contains only one Geometry. Geometry can be: Polyline (GeoLine), Arc (GeoArc), Circle (GeoCircle), Elliptic Arc (GeoEllipticArc), Ellipse (GeoEllipse), Parametric Line (GeoCompoundCurve), Poly Bezier (GeoBezier3Curve). In particular, when the subobject is GeoLine, the line Object Count can only be 1.
GeoMultiCurve
Parametric facets
It is composed of multiple sub-objects, and each sub-object contains only one Geometry. Geometry can be: Face (GeoRegion), Parametric Region (GeoCurvePolygon). In particular, when the sub-object is GeoRegion, The included face Object Count can only be 1.
GeoMultiSurface

External Formats Parametric Objects Import

Currently, the import of parameterized objects in DWG and FileGDB data is supported, and the import of parameterized objects is supported in windows _ x86, Linux _ x86 and Linux _ arm environments.

  • DWG
    DWGGeometry
    Import as line, Region Dataset
    Import as CAD Dataset
    Keep Parametric Object
    Not Keep Parametric Object
    Keep Parametric Object
    Not Keep Parametric Object
    Circle, ellipse
    Circle, ellipse
    Fitting polylines/faces
    Circle, ellipse
    Circle, ellipse
    Circular arc, elliptical arc
    Circular arc, elliptical arc
    Fitting polylines
    Circular arc, elliptical arc
    Circular arc, elliptical arc
    Spline curve
    Parametric Line
    Fitting polylines
    Parametric Line
    Fitting polylines
    Polyline
    Parametric Line
    Fitting polylines
    Parametric Line
    Compound
    Hatch
    Parametric Region
    Fitting surface
    Parametric Region
    Compound
    Block
    Parametric Line/Face
    Fitting polylines/fact
    Parametric Line/Face
    Compound

    * When a polyline is imported as a CAD Dataset, it can be imported as a parametric object only after the Keep Parametric Object "is set and a parametric object exists, and the polyline width is ignored or is 0. Otherwise, it can be imported as a Compound.

    * DWG is imported as a parametric object. It is only supported to be imported as a 2D Dataset. If you want to Keep Object Height information, it will be fitted as a polyline.

  • FileGDB
    FileGDBGeometry
    Lead-in, Region Dataset
    Circle, arc
    Circle, arc
    Poly Bezier
    Parametric multiline with Poly Bezier
    subobject
    Circle, Ellipse, Parametric Region
    Circle, Ellipse, Parametric Region
    Line/area feature consisting
    of multiple line regions (see Figure 2)
    Parametric Multiline/Parametric Facet

    * When FileGDB has multiple subobjects for a line/face feature (as shown in Figure 2 below), the import will be converted to a parametric multiline/parametric polyface containing multiple subobjects.

    composed of multiple subobjects
    Figure 2 Parametric multiline
  • Other External Formats Parametric objects imported in

    other external formats will be fitted as polylines.

Parametric Object Export External Format

Keep parameterized objects is currently supported only when exporting parameterized objects to DWG and DXF formats, and is supported in windows _ x86, Linux _ x86, and Linux _ arm environments. Export to other formats, including formats that do not support parametric objects, such as CSV, geojson, kml, etc. Parametric objects will be fitted to polylines.

Special instructions

For editing of parametric objects, currently only circles and ellipses are supported. Other ParametersAfter Object Editing, they will be fitted into polylines.

Functional support

Vector processing and analysis functions that currently support parameterized objects include: Overlay Analysis, Buffer Zone Analysis, Fusion, Regularize Building, Compute Area, Vector Resample, Extract Centerline from Two Lines、Extract Centerline from Polygon、Measure Distance、Line/Region Smoothing、 Create Random Point、Vector to Raster、Attribute Update、Edgematching、Vector Clip、Line Topology Processing、 Eliminate Small Polygons, face aggregation, Cluster and Outlier Analysis, Hotspot Analysis, and so on. For other functions not described, feedback can be given if parametric objects cannot be supported.