i.hyper.explore - GRASS GIS manual

NAME

i.hyper.explore - Visualize spectra from hyperspectral 3D raster maps.

KEYWORDS

SYNOPSIS

i.hyper.explore

i.hyper.explore --help

i.hyper.explore [-p] map=name[,name,...] [coordinates=east,north[,east,north,...]] [points=name] [output=name] [dpi=integer] [style_scale=float] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-p: Print JSON to stdout instead of plotting
--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

map=name[,name,...] [required]: Input 3D raster map(s) with hyperspectral data (comma-separated)
coordinates=east,north[,east,north,...]: Comma separated list of coordinates
points=name: Name of input vector map; Point vector map with query locations
output=name: Output plot file (.png, .pdf, .svg). If not set, opens an interactive window; Name for output file
dpi=integer: DPI value for output image (used only with output=); Default: 300
style_scale=float: Scale factor for fonts and line widths when exporting (e.g., 1.8); Default: 1.0

DESCRIPTION
FUNCTIONALITY
NOTES
EXAMPLES
DEPENDENCIES
AUTHORS

DESCRIPTION

i.hyper.explore visualizes spectra extracted from hyperspectral 3D raster maps (raster_3d). It allows users to interactively inspect spectral signatures at given map coordinates or from point vector maps. The module supports multiple 3D raster maps simultaneously for comparison (e.g., original data, preprocessed data, or reduced components).

Each queried location is sampled across all spectral bands using r3.what. The resulting spectral curves are plotted or printed in JSON format (with the -p flag). If an output file is specified (output=), the figure is exported instead of being shown interactively.

i.hyper.explore automatically reads wavelength metadata, measurement type (e.g., reflectance, radiance), and units from r3.info comments produced by i.hyper.import or i.hyper.preproc. If the map contains principal components or other dimensionally reduced features, the module detects this and adjusts the X-axis to component indices.

FUNCTIONALITY

Query spectra from one or more 3D raster maps at arbitrary locations.
Plot spectral curves for all queried points, automatically handling units and wavelength axes.
Detects whether the data represent reflectance, radiance, or dimensional components from metadata.
Export plots to .png, .pdf, or .svg via output=.
Optionally output structured JSON data for external analysis with the -p flag.
Automatically labels plots based on measurement type, units, and number of components.
Supports coordinate pairs (coordinates=) and vector point maps (points=).

NOTES

Each band’s wavelength and FWHM must be stored as comments in r3.info (automatically handled by i.hyper.import).
The module uses r3.what to extract band values at each 2D location.
If the raster represents dimensional components (e.g., PCA, NMF), the plot’s X-axis switches to “Components”.
The output plot resolution can be set with dpi=.
Line width and font size can be scaled with style_scale= (default: 1.0).
Line colors correspond to query points; linestyles correspond to input maps.
Interactive plots support renaming legends and saving figures directly from the viewer.

EXAMPLES

# Example 1: Compare spectra from EnMAP 3D raster map at two locations
i.hyper.explore map=enmap@PERMANENT \
                coordinates=4718536.78125,2587471.78125,4718504.625,2587623.375

# Example 2: Explore multiple spectra from Tanager 3D raster map
i.hyper.explore map=tanager@PERMANENT \
                coordinates=481043.478,8184411.261,483979.826,8180452.435,472444.174,8181841.957