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GRASS GIS 7.8.7 Reference Manual

       Geographic  Resources  Analysis  Support  System,  commonly referred to as GRASS GIS, is a
       Geographic Information System (GIS) used for  geospatial  data  management  and  analysis,
       image  processing, graphics/maps production, spatial modeling, and visualization. GRASS is
       currently used in academic and commercial settings around the world, as well  as  by  many
       governmental agencies and environmental consulting companies.

       This  reference  manual  details  the use of modules distributed with Geographic Resources
       Analysis Support System  (GRASS),  an  open  source  (GNU  GPLed),  image  processing  and
       geographic information system (GIS).  Go to imagery introduction | topics

       Go back to help overview

   Imagery commands:
       i.albedo                                                     Computes broad band albedo from surface reflectance.

       i.aster.toar                                                 Calculates Top of Atmosphere Radiance/Reflectance/Brightness
                                                                    Temperature from ASTER DN.

       i.atcorr                                                     Performs atmospheric correction using the 6S algorithm.

       i.biomass                                                    Computes   biomass   growth,   precursor   of   crop   yield
                                                                    calculation.

       i.cca                                                        Canonical   components  analysis  (CCA)  program  for  image
                                                                    processing.

       i.cluster                                                    Generates spectral signatures for land  cover  types  in  an
                                                                    image using a clustering algorithm.

       i.colors.enhance                                             Performs auto-balancing of colors for RGB images.

       i.eb.eta                                                     Actual  evapotranspiration for diurnal period (Bastiaanssen,
                                                                    1995).

       i.eb.evapfr                                                  Computes evaporative fraction and root zone soil moisture.

       i.eb.hsebal01                                                Computes sensible heat flux iteration SEBAL 01.

       i.eb.netrad                                                  Net radiation approximation (Bastiaanssen, 1995).

       i.eb.soilheatflux                                            Soil heat flux approximation (Bastiaanssen, 1995).

       i.emissivity                                                 Computes emissivity from NDVI,  generic  method  for  sparse
                                                                    land.

       i.evapo.mh                                                   Computes evapotranspiration calculation modified or original
                                                                    Hargreaves formulation, 2001.

       i.evapo.pm                                                   Computes  potential  evapotranspiration   calculation   with
                                                                    hourly Penman-Monteith.

       i.evapo.pt                                                   Computes evapotranspiration calculation Priestley and Taylor
                                                                    formulation, 1972.

       i.evapo.time                                                 Computes temporal integration of satellite ET  actual  (ETa)
                                                                    following  the  daily ET reference (ETo) from meteorological
                                                                    station(s).

       i.fft                                                        Fast Fourier Transform (FFT) for image processing.

       i.gensig                                                     Generates statistics for i.maxlik from raster map.

       i.gensigset                                                  Generates statistics for i.smap from raster map.

       i.group                                                      Creates, edits, and lists groups of imagery data.

       i.his.rgb                                                    Transforms raster maps from  HIS  (Hue-Intensity-Saturation)
                                                                    color space to RGB (Red-Green-Blue) color space.

       i.ifft                                                       Inverse Fast Fourier Transform (IFFT) for image processing.

       i.image.mosaic                                               Mosaics several images and extends colormap.

       i.in.spotvgt                                                 Imports SPOT VGT NDVI data into a raster map.

       i.landsat.acca                                               Performs  Landsat  TM/ETM+  Automatic Cloud Cover Assessment
                                                                    (ACCA).

       i.landsat.toar                                               Calculates top-of-atmosphere  radiance  or  reflectance  and
                                                                    temperature for Landsat MSS/TM/ETM+/OLI

       i.maxlik                                                     Classifies the cell spectral reflectances in imagery data.

       i.modis.qc                                                   Extracts quality control parameters from MODIS QC layers.

       i.oif                                                        Calculates Optimum-Index-Factor table for spectral bands

       i.ortho.camera                                               Select and modify the imagery group camera reference file.

       i.ortho.elev                                                 Select or modify the target elevation model.

       i.ortho.init                                                 Interactively  creates  or  modifies  entries  in  a  camera
                                                                    initial exposure station file for imagery  group  referenced
                                                                    by a sub-block.

       i.ortho.photo                                                Menu driver for the photo imagery programs.

       i.ortho.rectify                                              Orthorectifies   an  image  by  using  the  image  to  photo
                                                                    coordinate transformation matrix.

       i.ortho.target                                               Select or modify the imagery group target.

       i.ortho.transform                                            Computes a coordinate transformation based  on  the  control
                                                                    points.

       i.pansharpen                                                 Image   fusion  algorithms  to  sharpen  multispectral  with
                                                                    high-res panchromatic channels

       i.pca                                                        Principal components analysis (PCA) for image processing.

       i.rectify                                                    Rectifies an image by computing a coordinate  transformation
                                                                    for each pixel in the image based on the control points.

       i.rgb.his                                                    Transforms raster maps from RGB (Red-Green-Blue) color space
                                                                    to HIS (Hue-Intensity-Saturation) color space.

       i.segment                                                    Identifies segments (objects) from imagery data.

       i.smap                                                       Performs contextual image  classification  using  sequential
                                                                    maximum a posteriori (SMAP) estimation.

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

       i.target                                                     Targets an imagery group to a GRASS location and mapset.

       i.tasscap                                                    Performs Tasseled Cap (Kauth Thomas) transformation.

       i.topo.corr                                                  Computes topographic correction of reflectance.

       i.vi                                                         Calculates different types of vegetation indices.

       i.zc                                                         Zero-crossing "edge detection"  raster  function  for  image
                                                                    processing.

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       © 2003-2022 GRASS Development Team, GRASS GIS 7.8.7 Reference Manual