Calculate Geometry Attributes

Function Description

Calculate Geometry Attributes is to add the spatial or geometric Attributes of a vector object as a new Property Field. For example, Center Coordinates, Subobject Count, Geodesic Primeter, etc. The above Attributes are the metadata attributes of the object itself.

When the user needs to use its Attributes for operation and processing, it can be added as a new Property Field through the Calculate Geometry Attributes function without using other tools. And improves the work efficiency of processing geographic Spatial Data attributes. It adds one or more Property Fields to the current property sheet, depending on the options specified in the Geometric properties parameter.

Caution:

This action modifies the source data. If the user does not want to modify the source data, please back up the data before the operation.

Function entrance

  • Attribute sheet tab-> Edit group-> Calculate Geometry Attributes button to display the Calculate Geometry Attributes dialog.
  • Data tab-> Data Processing-> Vector-> Calculate Geometry Attributes.
  • Toolbox-> Data Processing-> Vector-> Calculate Geometry Attributes.

Parameter Description

  • Geometric Properties: Support the calculation of Geometric properties of multiple fields at one time. Calculate Result is stored through Specify Field, which supports specifying an existing field or a New Field. If you fill in an existing field name, the current field value will be overwritten by the Calculate Result. If you fill in a new field name, a new field will be added to save the Calculate Result. The fields need to be in one-to-one correspondence with the Geometric properties. Geometric properties vary slightly depending on the type of Vector Dataset selected.
    For example, if the selected Dataset is Point Dataset, only Center Coordinates (X/Y) can be selected for Geometric properties; If the selected Dataset is Region Dataset, the optional Geometric properties include Geodesic Area and Geodesic Primeter.
    • Center Coordinates (X/Y): It is divided into two attributes: CenterPointCoordinate _ Y and CenterPointCoordinate _ Y.
    • Centroid Coordinates (X/Y): divided into two attributes: CenterPointCoordinate _ Y and CenterPointCoordinate _ Y.
    • Geodesic Area: Add a Geodesic Area of the face object.

      Geodesic is a curve according to the radian of the earth surface, and Geodesic Area is the area of the curved surface. When Dataset is Geographic Coordinate System, the original algorithm is updated and improved to effectively reduce the calculation deviation under the influence of the earth curvature. O as to improve the accuracy of area calculation; when the Dataset is a Gauss _ Kruger (Xian 1980) and a Gauss _ Kruger (GCS2000) coordinate system, the accurate spherical area is calculated according to a Gauss coordinate inverse calculation formula provided by Technical Regulations for the Third National Land Survey; When the Dataset is other Projected Coordinate System and Planar Coordinate System, the plane area is calculated directly.

      Caution:

      Since the SuperMap 11i (2024) release, the Ellipsoid Area and Geodesic Area "algorithms have been improved and integrated. As a result, the Area of Ellipsoid option in Geometric properties is removed, and for a more accurate area Calculate Result, select Geodesic Area "to Calculate. If your model was set to calculate "Area of Ellipsoid" in the previous version, the Geometric properties parameter will automatically change to "Geodesic Area" "after Import Model in the new version.

    • Geode SiC Primeter: Add the Geodesic Primeter of the face object or the geodesic length of the line object.

      Geodesic is a curve according to the radian of the earth's surface. Geodesic Primeter is the perimeter of the surface. When Dataset is Geographic Coordinate System, it is already in ellipsoidal space. So the Geodesic Primeter is the same as the default SmPerimeter perimeter of the surface. When the Dataset is Projected Coordinate System and Planar Coordinate System, it is in the plane space, and the Geodesic Primeter and the object default SmPerimeter perimeter are the same. It is meaningful to calculate the Geodesic Primeter under the Geographic Coordinate System by specifying the Geographic Coordinate System to be calculated.

    • Subobject Count: Add the Subobject Count contained by the object.
    • Node Count: Add the Node Count of the line/face object.
    • Bound Coordinates: divided into four attributes of X/y coordinate maximum and minimum values.
    • Line Starting Point: divided into two attributes: LineStartPoint _ X and LineStartPoint _ Y.
    • Line midpoint: divided into two attributes: LineCenterPoint _ X and LineCenterPoint _ Y.
    • Line end point: It is divided into two attributes: LineEndPoint _ X and LineEndPoint _ Y.
    • Line Azimuth: Adds the azimuth of a line object.
    • Hole Counts: The number of holes to add a face object.
  • Length unit: It is used to specify the calculation unit when calculating Geodesic Primeter. It provides 9 common length units such as centimeter, decimeter, meter, kilometer, inch, foot and mile.
  • Area Unit: It is used to specify the calculation unit when calculating Geodesic Area. 14 common area units such as cm \ u00B2, DM \ u00B2, square meters, km \ u00B2, hectares and hectares are provided.
  • Coordinate System: The coordinate system used to calculate coordinates, lengths, and areas. The default is the coordinate system of the Current Data set.

Application example

The following figure shows the Dataset Properties table of Beijing urban boundaries. Calculate the three Geometric properties of Center Coordinates, Geodesic Area and Node Count respectively, and obtain the results shown in the right figure below.

Related topics

Reclassify Field

Update column

Update Column (ToDate)

Delete line/Add line

Undo/Redo

The property sheet is Copy and Paste.

Binary field editing