Resample Library Spectra (Image Analyst Tools)

Summary

Resamples the bands of a spectral library to match the bands of a target spectral library or image, producing a new spectral library file. The target spectral library or image can be predefined from a list of common sensors, or it can be based on a custom image or spectra.

Usage

The Output Library Spectra parameter value will be a spectra with the same number of bands and wavelength range as the Target sensor parameter value.
The operation is performed on bands with overlapping wavelengths. If the input has a greater range than the target, the excess bands will be discarded. If the target has a greater range than the input, the bands outside of the input range will not be included and will be designated with a negative value that can be defined as NoData.
For the Resampling Method parameter's Band averaging option, an input band will be included in the calculation based on whether its center wavelength falls within the target band's minimum and maximum wavelength range.
For the Resampling Method parameter's Gaussian convolution option, whether an input band will be included in the calculation is based on whether its center wavelength falls within the target's center wavelength ± 3σ as follows:

where FWHM = WavelengthMax – WavelengthMin.

Label	Explanation	Data type
Input Library Spectra	An Esri spectral library or ENVI spectral library file with wavelength information.	File; String
Output Library Spectra	The output Esri spectral library file with the resampled wavelength information.	File
Target sensor	Specifies the target spectra, or a custom spectra library file or image, that contains the target spectra. Landsat 9—The target spectra will be Landsat 9 satellite data with 7 bands. Landsat 8—The target spectra will be Landsat 8 satellite data with 7 bands. Landsat 7 (No thermal)—The target spectra will be Landsat 7 satellite data with 6 bands. Landsat 5 (No thermal)—The target spectra will be Landsat 5 satellite data with 6 bands. Landsat 4 (No thermal)—The target spectra will be Landsat 4 satellite data with 6 bands. Sentinel-3—The target spectra will be Sentinel-3 satellite data with 21 bands. Sentinel-2A—The target spectra will be Sentinel-2A satellite data with 13 bands. Sentinel-2B—The target spectra will be Sentinel-2B satellite data with 13 bands. ASTER bands 1-9—The target spectra will be ASTER satellite data with 10 bands. Custom target image or spectra—A custom spectral library file or image that contains the target spectra will be used. This is the default.	String
Custom Target Image or Spectra (Optional)	A custom spectral library file or image with wavelength information that contains the target spectra. This parameter is enabled when the Target sensor parameter value is Custom target image or spectra.	Raster Dataset; Mosaic Dataset; Mosaic Layer; Raster Layer; File; Image Service; String
Resampling Method (Optional)	Specifies the resampling method that will be used for the Output Library Spectra parameter value. Band averaging—A simple average of the input spectra based on all band values that fall within each target band's wavelength range will be used. This is the default. Gaussian convolution—A Gaussian model will be used to represent the spectral response function of the sensor, and the input band values will be weighted for each wavelength range.	String

ResampleLibrarySpectra(in_library_spectra, out_library_spectra, target_sensor, {custom_target_image_or_spectra}, {resampling_method})

Name	Explanation	Data type
in_library_spectra	An Esri spectral library or ENVI spectral library file with wavelength information.	File; String
out_library_spectra	The output Esri spectral library file with the resampled wavelength information.	File
target_sensor	Specifies the target spectra, or a custom spectra library file or image, that contains the target spectra. `LANDSAT-9`—The target spectra will be Landsat 9 satellite data with 7 bands. `LANDSAT-8`—The target spectra will be Landsat 8 satellite data with 7 bands. `LANDSAT-7_NO_THERMAL`—The target spectra will be Landsat 7 satellite data with 6 bands. `LANDSAT-5_NO_THERMAL`—The target spectra will be Landsat 5 satellite data with 6 bands. `LANDSAT-4_NO_THERMAL`—The target spectra will be Landsat 4 satellite data with 6 bands. `SENTINEL-3`—The target spectra will be Sentinel-3 satellite data with 21 bands. `SENTINEL-2A`—The target spectra will be Sentinel-2A satellite data with 13 bands. `SENTINEL-2B`—The target spectra will be Sentinel-2B satellite data with 13 bands. `ASTER_BANDS_1_TO_9`—The target spectra will be ASTER satellite data with 10 bands. `CUSTOM_TARGET_IMAGE_OR_SPECTRA`—A custom spectral library file or image that contains the target spectra will be used. This is the default.	String
custom_target_image_or_spectra (Optional)	A custom spectral library file or image with wavelength information that contains the target spectra. This parameter is active when the `target_sensor` parameter value is `CUSTOM_TARGET_IMAGE_OR_SPECTRA`.	Raster Dataset; Mosaic Dataset; Mosaic Layer; Raster Layer; File; Image Service; String
resampling_method (Optional)	Specifies the resampling method that will be used for the `out_library_spectra` parameter value. `BAND_AVERAGING`—A simple average of the input spectra based on all band values that fall within each target band's wavelength range will be used. This is the default. `GAUSSIAN_CONVOLUTION`—A Gaussian model will be used to represent the spectral response function of the sensor, and the input band values will be weighted for each wavelength range.	String

Code sample

ResampleLibrarySpectra example 1 (Python window)

This example uses the LANDSAT-8 option for the target_spectra parameter.

# Import system modules
import arcpy
from arcpy.ia import *

# Run ResampleLibrarySpectra
arcpy.ia.ResampleLibrarySpectra(r"c:\library\aspen.esl", r"C:\library\aspen_resampled.esl", "LANDSAT-8", "BAND_AVERAGING")

ResampleLibrarySpectra example 2 (stand-alone script)

This example uses the CUSTOM_TARGET_IMAGE_OR_SPECTRA option for the target_spectra parameter.

# Import system modules
import arcpy
from arcpy.ia import *

# Define variables
input_library = r"c:\library\hematite.sli"
out_library = r"c:\library\hematite_resampled.esl"
target_sensor = "CUSTOM_TARGET_IMAGE_OR_SPECTRA"
custom_target_image_or_spectra= r"c\image\landsat_7_bands.tif"
method = "GAUSSIAN_CONVOLUTION"

# Run ResampleLibrarySpectra
arcpy.ia.ResampleLibrarySpectra(
    in_library_spectra=input_library,
    out_library_spectra=out_library,
    target_sensor=target_sensor,
    custom_target_image_or_spectra=custom_target_image_or_spectra,
    resampling_method = method
)

Environments

This tool does not use any geoprocessing environments.

Licensing information