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CNASVDCreate Method

Create an NASVD object and perform SVD analysis

Namespace:  Geosoft.Desktop.GXNetX
Assembly:  geosoft.desktop.gxnetx (in geosoft.desktop.gxnetx.dll) Version: 2025.2.0.42
Syntax
Copy
public static CNASVD Create(
	CGXNETCore gxNetShared,
	CDB db,
	string channel,
	string mask_channel,
	int num_components,
	int start,
	int end
)

public static CNASVD Create(
	CGXNETCore gxNetShared,
	CDB db,
	string channel,
	string mask_channel,
	int num_components,
	int start,
	int end
)

Parameters

gxNetShared
Type: GeoEngine.Core.GXNetXCGXNETCore
A shared CGXNETCore
db
Type: GeoEngine.Core.GXNetXCDB
DB Object
channel
Type: SystemString
Spectral data channel name
mask_channel
Type: SystemString
mask_channel name (optional)
num_components
Type: SystemInt32
Number of eigenvectors to calculate (1 to min(M,N))
start
Type: SystemInt32
Inclusive starting index of the spectral data, ranging from (1, numChannels). Provide 1 or <define>GS_S4DM</define> to use the beginning of the spectrum.
end
Type: SystemInt32
Inclusive ending index of the spectral data, ranging from (1, numChannels). Provide numChannels or <define>GS_S4DM</define> to use the end of the spectrum.

Return Value

Type: CNASVD
NASVD Object
Remarks
Creates an NASVD object and performs the initial Hovgaard-normalized SVD analysis on the specified spectral channel data. The analysis extracts eigenvectors, scores, and singular values that can be used for spectral reconstruction and noise reduction. The input data is automatically normalized using the Hovgaard method before SVD. Results are stored internally in the NASVD object for later reconstruction use, including a line list of all lines that were used to calculate the eigenvectors. Subsequent spectra reconstruction will apply to the original list of lines used to create the NASVD object. It is common in radiometrics processing to exclude certain channels from smoothing operations. To facilitate this, 'start' and 'end' are provided as inclusive 1-based indices to define the range of spectral data to be used in the analysis. Use 1 or <define>GS_S4DM</define> for 'start' to indicate the beginning of the spectrum, and use <define>GS_S4DM</define> for 'end' to indicate the end of the spectrum. The optional mask channel allows the pre-selection of rows to include in the analysis. A dummy value in the mask channel indicates points not included. Valid data points should be indicated with "1".
See Also