---
name: "i.spectral"
section: "1grass"
platform: "linux"
package: "grass-doc"
version: "8.4.1-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/i.spectral"
---

# i.spectral(1grass)

Displays spectral response at user specified locations in group or images.

## NAME

**i.spectral**  - Displays spectral response at user specified locations in group or images.

## KEYWORDS

imagery, querying, raster, multispectral

## SYNOPSIS

**i.spectral**\
 **i.spectral --help**\
 **i.spectral** \[-**cgt**\]  \[**group**=*name*\]   \[**subgroup**=*name*\]   \[**raster**=*name*\[,*name*,...\]\]  **coordinates**=*east,north*\[,*east,north*,...\]  \[**output**=*name*\]   \[**format**=*string*\]   \[--**overwrite**\]  \[--**help**\]  \[--**verbose**\]  \[--**quiet**\]  \[--**ui**\]

### Flags:

- **-c**

  Show sampling coordinates instead of numbering in the legend (valid for -g flag)

- **-g**

  Use gnuplot for display

- **-t**

  output to text file

- **--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:

- **group**=*name*

  Name of input imagery group

- **subgroup**=*name*

  Name of input imagery subgroup

- **raster**=*name\[,name*,...\]

  Name of input raster map(s)

- **coordinates**=*east,north\[,east,north*,...\] **\[required\]**

  Coordinates

- **output**=*name*

  Name for output image is valid for -g (or text file for -t flag)

- **format**=*string*

  Graphics format for output file (valid for -g flag)\
   Options: *png, eps, svg*\
   Default: *png*

## DESCRIPTION

*i.spectral* displays spectral response at user specified locations in images.

## NOTES

This script requires the launch of one of the supported monitors (cairo, png, ps) or gnuplot to be installed.

## EXAMPLE

Analysis of LANDSAT TM7 channels (North Carolina dataset):\

```
g.region raster=lsat7_2002_10 -p
i.spectral -g raster=lsat7_2002_10,lsat7_2002_20,lsat7_2002_30,lsat7_2002_40,lsat7_2002_50,lsat7_2002_70 \
           coordinates=636069,215440,637958,223393,633277,223605
```

Spectral plot of 3 different land cover types: (1) water, (2) green vegetation, and (3) highway

North Carolina sample dataset:\

```
g.region raster=lsat7_2002_10 -p
LIST=`g.list type=raster pattern="lsat7_2002_[1-5,7]0" separator=","`
d.mon start=cairo output=plot.png
i.spectral raster=$LIST coordinates=637502.25,221744.25
d.mon stop=cairo
```

This will search all LANDSAT map for 2002 but select only the B, G, R, NIR, and MIR channels.

## SEE ALSO

*d.where,* *r.what,* *Cairo driver,* *PNG driver,* *PS driver (Postscript)*

## AUTHORS

Markus Neteler\
 Francesco Pirotti

## SOURCE CODE

Available at: i.spectral source code (history)

Accessed: Monday Feb 24 17:51:44 2025

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