Appendix 5: IPW Commands

1. IPW general-purpose commands

Information

ipw		-- list IPW command directories
ipwman		-- extract header comments from IPW source
ipwfile		-- return description of an IPW image

Generic Image Processing

hist		-- compute image histogram
lutx		-- apply lookup table to image
bitcom		-- bitwise band combination
lincom		-- linear combination of bands
mult		-- multiply bands together
mstats		-- image multivariate statistics
convolve	-- image convolution
gradient	-- slope and aspect of image

Image Utilities

window		-- extract image window
mux		-- multiplex (band-interleave) images
demux		-- extract image bands
transpose	-- transpose an image
flip		-- flip IPW image
skew		-- skew image lines
zoom		-- minify/magnify by subsampling/replication
cmpimg		-- compare two images
edimg		-- edit image
primg		-- print image pixels

Image Conversion

ipw2pbm		-- convert IPW image to PGM or PPM formats
ipw2ps		-- convert image to PostScript
pbm2ipw		-- convert PNM image IPW format
dither		-- convert to 1-bit pixels by dithering

Headers

mkbih		-- make an IPW basic image header
mkgeoh		-- add a geodetic header to an image
mklqh		-- construct a linear quantization (LQ) header
mksath		-- make satellite header
mksunh		-- make an IPW sun header
mkwinh		-- make an IPW window header
prhdr		-- print IPW image headers
rmhdr		-- strip IPW image headers
edhdr		-- edit image header

Radiation Modeling

hor1d		-- find angles to local horizon along rows of elevation file
horizon		-- find horizon in direction "azimuth"
sunang		-- calculates sun angles
shade		-- cosine of illumination angle
viewcalc	-- sky view & terrain configuration factors
viewf		-- sky view and terrain configuration

Miscellaneous Commands

cnhist		-- convert IPW histogram to cumulative normalized ASCII
interp		-- interpolate between breakpoints
lqhx		-- transform image to new linear quantization (LQ) header
mklut		-- make look-up table
poly		-- fill polygon
random		-- print random values
wedge		-- linear combination of line, sample coordinates

IPW user-contributed commands

CRREL

blank		-- create blank (DN=0) image
fill		-- fill areas by region growing
getsig		-- compute signature file
ipwdemo		-- link demonstration image directories
laplace		-- laplacian filter
linelen		-- compute line lengths
merge		-- merge coordinates files
prls		-- print line and sample coordinates
scribe		-- draw on image

UCSB Geography Department

Image Processing

addc		-- scale image by constant
histeq		-- make histogram equalization look-up table
interp3		-- interpolate 3 color (rgb) input 
mkkern		-- make convolution kernel 
mm		-- calculate minimum and maximum dn values from a histogram
prhist		-- print histogram values
ratio		-- compute image ratio
rgbmklut	-- make red-green-blue look-up table
rgbmux		-- 8-bit color composite

Image Classification

bayes		-- bayesian classifier
jmdist		-- compute divergence (J-M distance) 
pscohist	-- display cospectral histograms in Postscript format
tekcohist	-- display cospectral histograms on tektronix window

Principal Component Analysis

eigen		-- interface to jacobi to compute eigen vectors
jacobi		-- compute eigenvalues and eigenvectors 

Image Conversion

bil2bip		-- convert band-interleaved by line to band-interleaved by pixel

UCSB CRSEO

mfilter		-- median filter smoothing in 1-dimension
topcal		-- redo antenna radiometric calibration
toparam		-- topgraphic parameters

Boston University

cluster		-- cluster a region table
dendrogram	-- draw dendrogram graph 
insert		-- overlays images
liststand	-- generate a stand list
rmap_to_tab	-- computes information from a region map
rtbl_to_lut	-- converts region table to mklut input
segment		-- segment an IPW image by region growing
texture		-- texture an IPW image
ucluster	-- cluster training statistics using Bhattacharrya distance
ustats		-- unsupervised cluster-based classification

EPA Corvalis (Longely, Marks 1991)

Snow melt modeling

isnobal		-- 2-layer energy balance snowmelt model 
salbedo		-- Estimates solar albedo over snow in two channels 
selevrad	-- topographic distribution of beam & diffuse radiation over snow 
stoporad	-- topographic distribution of solar radiation over snow 

Solar radiation modeling

gelevrad	-- global-scale beam and diffuse radiation (preprocessor for gtoporad) 
ggradient	-- slope and aspect of global-scale image 
ghorizon	-- cosine horizon angles for global-scale elevation image 
gshade		-- cosine of illumination angle 
gsunlight	-- Sun angles for global scale image 
gtoporad	-- global-scale topographic distribution of solar radiation 
gtoporad.24	-- global-scale topographic distribution of solar radiation at even time intervals for 24 hours 
gtopquad	-- daily integrated radiation over global-scale topographic grid
gviewf		-- sky view and terrain configuration 
sunweights	-- Kronrod quadrature weights 
toporad.24	-- solar radiation over topographic grid at even time intervals for a total of 24 hours 

Map projection conversion

mkalbers	-- create Albers projection definition file 
mkgeo		-- create geographic projection definition file 
mklambert	-- create Lambert Azimuthal Equal Area projection definition file 
mklamcc		-- create Lambert Conformal Conic projection definition file 
mkutm		-- create UTM projection definition file 
reproj		-- convert image to new geographic projection 
reproj_area	-- calculate minimum bounding rectangle in reprojected space
transcoord	-- translate map coordinates to different map projection 

Image classification

classeq		-- classify image according to equal area histogram 
classify	-- classify image by given class ranges 
clmask		-- make mask image from classified image 
declass		-- classify image according to equal area histogram 
mkcrh		-- construct a class range (CR) header 

Image file import/export/interpolation utilities

binexp		-- export binary floating point image data 
grass.to.ipw	-- converts GRASS cell file to IPW image (run from GRASS)
hcnx		-- Extract daily hydro-climatological or streamflow data
ipw.to.grass	-- Convert IPW image file to GRASS cell file (run from GRASS)
import		-- import ASCII file to IPW image 
ipw2las		-- convert LAS image to IPW image 
las2ipw		-- convert LAS image to IPW image 
surface		-- interpolate image from irregularly spaced point data 

Other models

ipott		-- Calculate potential temp or air temp 
itrbxfr		-- calculate H & LE using Brutsaert's method 
rh2vp		-- convert relative humidity to vapor pressure 
wbal		-- simple water balance model 

Image file utilities

cnhist.all	-- cumulative normalized histogram of one or more images 
ftransform	-- transform image according to floating point X,Y pairs 
imgstat		-- image statistics 
imgsum		-- sum all unmasked pixels in an image 
lqmm		-- min and max of all LQ header(s) 
pix2fp		-- convert raw pixel to floating-point 
requantize	-- requantize one or more images 
resamp		-- zoom image by aggregation of pixel data - taking mean, min, or max 

Other

addtime		-- add delta hours to given date/time 
cvtime		-- Converts between time formats