Transform Dataset Coordinate System

Instructions for Use

Perform a Projection Transformation on the Source Dataset according to the Target Coordinate System, and the result will directly change the Projected Coordinate System of the Source Dataset. Currently, only coordinate system conversion is supported for Vector Dataset.

The Parameter Settings for the tool vary depending on the Projection Transformation Method you set. The Projection Transformation method can be generally divided into a three-parameter transformation method and a seven-parameter transformation method:

  1. Three-parameter conversion method

When the frame of reference is converted, a relatively simple conversion method is the so-called three-parameter conversion method. This transformation method is based on the mathematical model that only the coordinate origin of the space has been translated between the two Geodetic Reference System, without considering other factors (see Figure 1). This method inevitably produces three parameters, the translation of X, Y and Z directions. The three-parameter transformation method is simple in calculation, but low in accuracy, and is generally used for the transformation between different geocentric Space Rectangular Coordinates.

  1. Seven-parameter conversion method

The mathematical model based on the seven-parameter method considers not only the translation of the coordinate system, but also the rotation of the coordinate system and the different scales. Therefore, in addition to the three translation quantities, three rotation parameters (also known as three Euler angles) and Scale Factor (also known as Scale Factor) are required. The conversion principle is shown in Figure 2. The three translation quantities are represented by ΔX, ΔY and ΔZ, the three rotation Transformation Parameters are represented by Rx, Ry and Rz, and the Scale Factor is represented by S. Where Scale Factor represents the amount of scaling from the original coordinate system to the new coordinate system. In general, the unit of translation factor is meter (consistent with Unit), the unit of Rotation angle is second, and the units are one in a million. Of Scale Factor.

  1. geocentric transformation (the Geocentric Translation), Molodensky transformation, The simplified Molodensky Abridged transformation method belongs to the Projection Transformation method with lower accuracy. The three-parameter transformation method requires three translation Transformation Parameters (ΔX, ΔY, ΔZ), and the Molodensky transformation method and the simplified Molodensky transformation method also require three translation Transformation Parameters (ΔX, ΔY, ΔZ). In the case of low data accuracy requirements, these methods can generally be used.

  2. Position Vector method, Coordinate Frame method and Bursa-Wolf method are the methods with high precision. Seven parameters are required for adjustment and transformation, including three translational Transformation Parameters (.DELTA.X.DELTA.Y.DELTA.Z), three rotational Transformation Parameters (Rx, Ry, Rz), and a scale parameter (S). These methods are exactly the same, but due to different countries, regions or schools of measurement, the customary appellation is different.

In practical work, which conversion method is used depends on the specific situation. The satisfactory result of the transformation depends on the setting of the Transformation Parameters. Transformation Parameters can be obtained from official measurement agencies and data providers, or can be measured and calculated. The suitability of the Transformation Parameters must be determined by the presence of control points in both frames of reference.

Parameter Description

Parameter name Default Parameter description Parameter type
Source data   Source Dataset for coordinate system conversion. In the Geo-Processing Automation (GPA) WebUI interface of iServer, the Dataset can be specified in the "Set Connection Info" dialog box by clicking the "Set" button on the right side of the parameter. And support Dataset in various Datasource types. ! Alternatively, you can open a Dataset with the Open Dataset tool and, Assign the returned Dataset to the Source Data Input Parameter of the Transform Dataset Coordinate System "tool through connection, as shown in the following figure. The opened Dataset is dynamically assigned to the corresponding parameter of the Transform Dataset Coordinate System "tool. ! This shows that the "Source Data" Input Parameter of the "Transform Dataset Coordinate System" "tool can also be connected. Result Dataset passed in from other Geo-Processing Automation (GPA) tool output. Dataset
Target Coordinate System   Target Coordinate System after Source Data Conversion. In the Geo-Processing Automation (GPA) WebUI interface of iServer, the parameter needs to input the EPSG code corresponding to the coordinate system. For example, the parameter value is 4326. Represents the WGS 1984 Geographic Coordinate System; In the iDesktop XGeo-Processing Automation (GPA) interface, this parameter can be set through a dialog box, as shown in the following figure:! . PrjCoordSys
Scale Difference 0.0 This parameter is the Scale Factor, which represents the amount of scaling from the original coordinate system to the new coordinate system. Double
Rotation angle X 0.0 Rotation Transformation Parameters, representing the rotation angle of the X axis, in seconds. Double
Rotation angle Y 0.0 Rotation Transformation Parameters, representing the rotation angle of the Y-axis, in seconds. Double
Rotation angle Z 0.0 Rotation Transformation Parameters, representing the rotation angle of the Z axis, in seconds. Double
Offset X 0.0 Coordinate offset of the X axis (offset is also known as translation). Double
Offset Y 0.0 Coordinate offset of the Y axis (offset is also known as translation). Double
Offset Z 0.0 Coordinate offset of the Z axis (offset is also known as translation). Double
Rotated origin X coordinate 0.0 Amount of rotated origin X coordinate. Double
Rotated origin Y coordinate 0.0 Rotated origin Y coordinate amount. Double
Rotated origin Z coordinate 0.0 Rotated origin Z coordinate amount. Double
Projection Transformation Method Method used by the MTH _ GEOCENTRIC _ TRANSLATION Projection Transformation. SuperMap provides several common projection transformation methods. See the "Projection Transformation Method" table below for details. CoordSysTransMethod

Table: Projection Transformation method

Name Description
MTH _ GEOCENTRIC _ TRANSLATION GeocentricTranslation Geocentric-based three-parameter translation method.
MTH MOLODENSKY Molodensky conversion method, three-parameter conversion method.
MTH MOLODENSKY ABRIDGED Molodensky Abridged Simplified Molodensky Transformation, Three-Parameter Transformation.
MTH POSITION VECTOR Position Vector method, seven parameter conversion method.
MTH COORDINATE _ FRAME CoordinateFrame Geocentric based seven parameter conversion method.
MTH BURSA WOLF Bursa-Wolf method, seven-parameter transformation method.
MolodenskyBadekas MolodenskyBadekas Projection Transformation Method, a ten-parameter spatial Coordinate Transformation model.
China _ 3D _ 7p 3D seven-parameter conversion model for conversion between different coordinate systems and the National Geodetic Coordinate System 2000 (CGC2000). It is applicable to Coordinate Transformation of control points between geodetic Coordinate Systems under different earth ellipsoid datum of 3 degrees and above of national and provincial ellipsoid. The model involves three translation parameters, three rotation parameters and one scale change parameter, and at the same time, it needs to take into account the two major semi-axes of the earth ellipsoid and the flattening difference corresponding to the two geodetic coordinate systems.
CHINA _ 2D _ 7P CHINA _ 2D _ 7P Two-dimensional seven-parameter transformation model for the transformation between different coordinate systems and the National Geodetic Coordinate System 2000 (CGC2000). It is applicable to national and provincial Coordinate Transformation of control points between geodetic Coordinate Systems under different earth ellipsoid datum of 3 degrees and above. The model involves three translation parameters, three rotation parameters and one scale variation parameter. For the transformation from Beijing Coordinate System 1954 and Xi'an Coordinate System 1980 to China Geodetic Coordinate System 2000, it is suggested to adopt the two-dimensional seven-parameter transformation because of the low accuracy of the geodetic height under the two reference-centered systems.
China _ 2D _ 4P 2D four-parameter transformation model for transformation between different coordinate systems and the National Geodetic Coordinate System 2000 (CGC2000). It is applicable to Coordinate Transformation of local control points within 2 degrees at provincial level and below. The model involves three translation parameters and one scale variation parameter.
MTH _ Prj4 PROJ4 TransmethodProjection Transformation algorithm, which is based on the PROJ4 third-party Projection Transformation tool. So as to support more Projection Transformation operations and meet the data Projection Transformation requirements of more overseas users. The Projection Transformation algorithm only supports the transformation between projections with corresponding EPSG Code.
MTH _ EXTENTION Users provide projection extension function through SuperMap, and realize the conversion of projection and Geographic Coordinate System by writing custom conversion algorithm.
BD09toGCJ02 Baidu coordinate system to Mars coordinate system.
GCJ02TOBD09 Mars coordinate system to Baidu coordinate system.
GCJ02TOWGS84 MARS COORDINATE TO WGS84.
WGS84TOGCJ02 WGS84 to the Mars coordinate system.

Output Result

Parameter name Parameter description Parameter type
Result Dataset Result Dataset Dataset