r.in.ermapper?

[Rod Paterson]

Simon, 
      Here are two scripts which allow Grass raster import export
      from ERMapper. 

This script will build a Grass header file for your new image in cellhd 
by examining the ERMapper header and extracting the parts required.It then 
links the ERMapper image into your cell directory so that you don't have to 
have two copies on your disk.

#### Start Import Shell Script ####
-------------------------------------cut here
#!/bin/sh
#
# This shell script will create a GRASS cellhd file from an ER Mapper .ers
# file.  This is a temporary program - a more comprehensive version in C is
# currently under development.  However, this shell script program does show
# how easy it is to copy from ER Mapper's ASCII format header files in to other
# formats.
#
if [ "$#" -ne "2" ]
then
echo "Use full path to ERMapper image from within a GRASS shell"
echo "Do not include the .ers extension"
echo "Usage: import_ermapper_to_grass <file> $LOCATION/cellhd/<file>"
exit 1
fi
ln -s $1 $LOCATION/cell/$2
ERS=$1.ers
GRASS=$LOCATION/cellhd/$2
echo > $GRASS "# GRASS $GRASS cellhd file created from ER Mapper $ERS file"
tr < $ERS '[a-z]' '[A-Z]' | awk -F= '
BEGIN {
        offsetx = 0.0;
        offsety = 0.0;
        xdim = 0.0;
        ydim = 0.0;
        regx = 0.0;
        regy = 0.0;
        nrows = 0;
        ncols = 0;
        bytorder = 0;
        form = 0;
}
/PROJECTION/               { proj = $2 }
/REGISTRATIONCELLX/        { offsetx = $2 }
/REGISTRATIONCELLY/        { offsety = $2 }
/METERSX/ || /EASTINGS/    { regx = $2 }
/METERSY/ || /NORTHINGS/   { regy = $2 }
/XDIMENSION/               { xdim = $2 }
/YDIMENSION/               { ydim = $2 }
/NROFLINES/                { nrows = $2 }
/NROFCELLSPERLINE/         { ncols = $2 }
/NROFBANDS/                { nbands = $2 }
/UNSIGNED8BITINTEGER/      { form = 0 }
/UNSIGNED16BITINTEGER/     { form = 1 }
/UNSIGNED32BITINTEGER/     { form = 2 }
/IEEE[48]BYTEREAL/         { print "ERROR - FLOAT NOT SUPPORTED BY GRASS" }
/ SIGNED8BITINTEGER/       { print "ERROR - SIGNED INTS NOT SUPPORTED BY GRASS"
 }
/HEADEROFFSET/             { print "ERROR - HEADEROFFSET NOT SUPPORTED BY GRASS
 - USE OUTPUT TO DATASET" }
/BYTEORDER/                { bytorder = $2 }
END {
            if (bytorder == LSBFIRST) print "ERROR - LSB byteorder NOT SUPPORTE
D BY GRASS";
            if (nbands > 1) print "ERROR - GRASS ONLY SUPPORTS ONE BAND - USE O
UTPUT TO DATASET"; 
            if (substr(proj,1,7) ~ /\"*TM*/) print "proj:            1";
                 else print "proj:        UNKNOWN" ;
            if (substr(proj,1,7) ~ /\"*TM*/) zone = (substr(proj,8,2));
                 else zone = 1;
        printf("zone:            %s\n", zone); 
        printf("north:           %f\n", regy + (offsety * ydim));
        printf("south:           %f\n", regy - ((nrows-offsety) * ydim));
        printf("east:            %f\n", regx + ((ncols-offsetx) * xdim));
        printf("west:            %f\n", regx - (offsetx * xdim));
        printf("cols:            %d\n", ncols);
        printf("rows:            %d\n", nrows);
        printf("e-w resol:       %f\n", xdim);
        printf("n-s resol:       %f\n", ydim);
        printf("format:          %d\n", form);
        printf("compressed:      0")
}
' >> $GRASS
-------------------------------------cut here
#### END Import Shell Script ####

The script should be placed in your path ie./usr/local/bin
and executed with two file name arguments.
The first is the "absolute path" to the ERMapper image and the second is 
the name for the GRASS cell file
Please note I have not tried to use this script with LAT LONG datasets
so you might experience some problems here but it works well with UTM.

I have also included a script to take GRASS rasters to ERMapper which
you might also find useful.

#### Start Export Shell Script ####
-------------------------------------cut here
#!/bin/sh
#
# This shell script will create a .ERS file from a GRASS4.1 image (cell directo
ry)
# file.
#

if [ "$#" -ne "2" ]
then
echo "Usage: export_grass_to_ermapper $LOCATION/cellhd/<file> $GISDBASE/$LOCATI
ON_NAME/<file>"
exit 1
fi
GRASS=$LOCATION/cellhd/$1
ERS=$GISDBASE/$LOCATION_NAME/$2.ers
echo > $ERS "# ER Mapper $ERS file created from $GRASS file."
tr -d < $GRASS [:] | tr [a-z] [A-Z] | awk '
BEGIN {
        proj = 0;
        comp = 0;
        zone = 0;
        xdim = 0.0;
        ydim = 0.0;
        regx = 0.0;
        regy = 0.0;
        nbands = 1;
        ncols = 0;
        nrows = 0;
        nbits = 0;

}
/PROJ/                  { proj = $2 }
/ZONE/                  { zone = $2 }
/NORTH/                 { regy = $2 }
/WEST/                  { regx = $2 }
/COLS/                  { ncols = $2 }
/ROWS/                  { nrows = $2 }
/E-W/                   { xdim = $3 }
/N-S/                   { ydim = $3 }
/FORMAT/                { nbits = $2 }
/COMPRESSED/            { comp = $2 }
END {
print
printf("DatasetHeader Begin\n");
printf("\tVersion       = \"4.1\"\n");
printf("\tDataSetType   = ERStorage\n");
printf("\tDataType      = Raster\n");
printf("\tByteOrder     = MSBfirst\n");
printf("\tCoordinateSpace Begin\n");
printf("\tDatum = \"AGD66\"\n");
printf("\t%s%s%d%s\n","Projection       = ","\"TMAMG",zone,"\"");
printf("\tCoordinateType = EN\n");
printf("\tUnits = \"Meters\"\n");
printf("\tRotation      = 0:0:0.0\n");
printf("\tCoordinateSpace End\n");
printf("RasterInfo Begin\n");
        if(nbits=="0")
printf("\tCellType      = Unsigned8BitInteger\n");
        else
        if(nbits=="1")  
printf("\tCellType      = Unsigned16BitInteger\n");
        else
        if(nbits=="2")
printf("\tCellType      = Unsigned32BitInteger\n");
printf("\tNullCellValue = 0\n");
printf("\tCellInfo Begin\n");
printf("\t\tXdimension = %f\n",xdim+0);
printf("\t\tYdimension = %f\n",ydim+0);
printf("\tCellInfo End\n");
printf("\tNrOfLines = %d\n",nrows+0);
printf("\tNrOfCellsPerLine = %d\n",ncols+0);
printf("\tRegistrationCoord Begin\n");
printf("\tEastings  = %d\n",regx+0);
printf("\tNorthings = %d\n",regy+0);
printf("\tRegistrationCoord End\n");
printf("\tNrOfBands = %d\n",nbands+0);
printf("\tRasterInfo End\n");
printf("DatasetHeader End\n");
}
' >> $ERS
ln -s $LOCATION/cell/$1 $GISDBASE/$LOCATION_NAME/$1
-------------------------------------cut here
#### END Export Shell Script ####

Note:ERMapper requires that the GRASS raster be uncompressed
     before it can read it. This has some implications for
     management of disk storage space as some high resolution
     (small cell dimension) files can become very large.
     It would be easy enough to include the r.compress step
     in this script.

     Both scripts expect to be run from within GRASS as
     they rely on the GRASS environment variables.


        Good Luck

        Rod Paterson
        Aberfoyle Resources Ltd
        Phone: 61-3-8822226
        Fax:   61-3-8131086
        Email: rgp at aberfoyle.oz.au