Feature Description
A ground control point (GCP) is a control point located at a specific position and on a specific target in an image, with coordinate information in the mapping coordinate system. Due to its high-precision spatial coordinate data, it can be used in processes such as remote sensing imagery geometric correction, positioning accuracy verification, and spatial registration to achieve high-precision geographic referencing and positional tracking of image data.
SuperMap iDesktopX11i(2023) starts to support this feature.
Parameter Description
| Parameter Name | Parameter Interpretation | Parameter Type |
| Dataset |
Displays the dataset containing the image used for generating ground control points. It is not editable. |
DatasetMosaic |
| Input Image Type | Selects the type of image used for generating ground control points. The default is Panchromatic Image. It can also be switched to Multispectral Image, Forward-looking Image, Rear-view Image, or Front View and Rear View Image according to specific circumstances. | ComboBoxImageType |
| Error Threshold | The error threshold for gross error elimination in image matching. The value range is [0,40]. The default is 5, and the unit is px. During the image matching process, the least squares method is used to fit the result points, and points exceeding the error threshold are removed. A larger threshold preserves more tie points but increases the probability of retaining incorrect points. | Double |
| Point Distribution Mode |
Selects the ground control point distribution mode. Two methods are provided: Conventional and Uniform. The default is Conventional.
|
PointDistributionMethod |
| Number of Blocks in Column Direction |
Available after selecting Conventional in Point Distribution Mode. The number of blocks into which each scene image is divided in the column direction. The default value is 4. |
Integer |
| Number of Blocks in Row Direction |
Available after selecting Conventional in Point Distribution Mode. The number of blocks into which each scene image is divided in the row direction. The default value is 4. |
Integer |
| Matching Method |
Available after selecting Conventional in Point Distribution Mode. Provides the following six matching methods to choose from based on data characteristics and requirements. Among them, the AFHORP and RIFT methods support multi-modal data matching; CASP and DEEPFT are based on deep learning and require additional AI model configuration and CUDA environment installation. Generally, MOTIF, CASP, or DEEPFT are recommended.
|
ImageMatchMethod |
| Maximum Points per Block |
Available after selecting Conventional in Point Distribution Mode. The maximum number of points retained within each image block during image matching. The value range is [1,2048], and the default is 256. |
Integer |
| Number of Seed Points |
Available after selecting Uniform in Point Distribution Mode. Sets the number of seed points for conjugate point matching on each scene image. The value range is [64,6400], and the default is 512. When the image texture is poor, it is recommended to increase the number of ground control points to match enough points and improve subsequent imagery quality. |
Integer |
| Seed Point Search Method |
Available after selecting Uniform in Point Distribution Mode. Sets the method for searching seed points. The default is Raster Center Point.
|
SearchSeedPointMethod |
| Template Size |
Available after selecting Uniform in Point Distribution Mode. Sets the interval size between seed points. The value range is [1,256], the default is 40, and the unit is px. A larger template leads to more reliable searched points but longer processing time. |
Integer |
| Search Radius |
Available after selecting Uniform in Point Distribution Mode. Sets the search radius for seed points in image matching. The value range is [0,256], the default is 40, and the unit is px. A larger search radius increases the matching range but also increases the processing time. |
Double |
| Semantic Culling of Non-Ground Points | Not checked by default. When checked, ground control points within cloud areas and building areas can be automatically culled based on AI semantic technology. | Boolean |
| Cloud Area |
Available after Semantic Culling of Non-Ground Points is checked. Checked by default, meaning ground control points within cloud areas will be automatically culled based on the set dataset. If unchecked, ground control points in cloud areas will be retained. The dataset must contain an ImageName field, and the name must correspond to the image currently to be processed. |
Boolean |
| Dataset |
Displayed after "Cloud Area" is checked. Not editable. For workflows related to DOM production, use the cloud amount data from Set the Image Path. For workflows related to DSM production, use the cloud amount data from Set Image Path (dsm/dem). |
DatasetVector |
| Building Area | Available after Semantic Culling of Non-Ground Points is checked. Checked by default, meaning building areas will be automatically identified and ground control points within these areas will be culled. If unchecked, ground control points in building areas will be retained. | Boolean |
Output Result
Generates a GroundControlPoint vector point dataset in the Control Point datasource.
Related Topics
References
[1] Chen, P., Yu, L., Wan, Y., Pei, Y., Liu, X., Yao, Y., ... & Zhang, Y. (2025). CasP: Improving Semi-Dense Feature Matching Pipeline Leveraging Cascaded Correspondence Priors for Guidance. In Proceedings of the IEEE/CVF International Conference on Computer Vision (pp. 28063-28072).