Sample Extraction¶

Detailed description¶

The application extracts samples values from animage using positions contained in a vector data file.

Parameters¶

This section describes in details the parameters available for this application. Table [1] presents a summary of these parameters and the parameters keys to be used in command-line and programming languages. Application key is SampleExtraction .

InputImage Support image.

Input sampling positions Vector data file containing samplingpositions. (OGR format).

Output samples Output vector data file storing samplevalues (OGR format). If not given, the input vector data file is updated.

Output field names Choice between naming method for output fields. Available choices are:

• Use a prefix and an incremental counter : Use a prefix and an incremental counter

• Output field prefix : Prefix used to form the field names thatwill contain the extracted values.
• Use the given name list : Use the given name list

• Output field names : Full list of output field names.

Field Name Name of the field carrying the classname in the input vectors. This field is copied to output.

Layer Index Layer index to read in the input vector file.

Available RAM (Mb) Available memory for processing (in MB).

Load otb application from xml file Load otb application from xml file.

Save otb application to xml file Save otb application to xml file.

Example¶

To run this example in command-line, use the following:

otbcli_SampleExtraction -in support_image.tif -vec sample_positions.sqlite -outfield prefix -outfield.prefix.name band_ -field label -out sample_values.sqlite

To run this example from Python, use the following code snippet:

#!/usr/bin/python

# Import the otb applications package
import otbApplication

# The following line creates an instance of the SampleExtraction application
SampleExtraction = otbApplication.Registry.CreateApplication("SampleExtraction")

# The following lines set all the application parameters:
SampleExtraction.SetParameterString("in", "support_image.tif")

SampleExtraction.SetParameterString("vec", "sample_positions.sqlite")

SampleExtraction.SetParameterString("outfield","prefix")

SampleExtraction.SetParameterString("outfield.prefix.name", "band_")

SampleExtraction.SetParameterString("field", "label")

SampleExtraction.SetParameterString("out", "sample_values.sqlite")

# The following line execute the application
SampleExtraction.ExecuteAndWriteOutput()