ossim-chipper

ossim-chipper is a command line application used to generate elevation products from raw dem, dted, and srtm data. This application supports 2 basic functions: hillshade and color-relief. From these 2 operations you can create the following products.

Color Relief

Color Relief is used to generate an RGB or ARGB representation of a dem. Different colors are used to represent elevation bands. Users will provide a template with corresponding colors values.

ossim-chipper --op color-relief --color-table template.kwl --srs EPSG:4326 
input.src output.jpg

Command line without dot.src file with lots of options:

ossim-chipper -t 512 --resample-filter BILINEAR  --op color-relief --color-table color-relief-lut1.kwl --output-radiometry U8 --writer-prop compression_quality=75 --writer-prop create_world_file=1 --writer-prop pixel_type=point --cut-bbox-ll 39.452331542969  -106.75654602051 40.507019042969 -105.43818664551 /data1/elevation/dted/level1/w107/n39.dt1 /data1/elevation/dted/level1/w107/n40.dt1  /data1/elevation/dted/level1/w106/n39.dt1 /data1/elevation/dted/level1/w106/n40.dt1 t1.tif

There is a color relief template on:

​http://trac.osgeo.org/ossim/browser/trunk/ossim/etc/templates/ossim-chipper-color-table-template.kwl

Hillshade

Hillshade is used to generate a shaded relief. It requires the following inputs:

• Sun Azimuth
• Sun Elevation
• Vertical Exaggeration
• Color (either RGB or Color Table)

Example:

ossim-chipper --op hillshade --azimuth 270 --elevation 45 --exaggeration 10
--color 222,229,188 --srs EPSG:4326 input.src output.jpg

Example with color table:

ossim-chipper --op hillshade --azimuth 270 --elevation 45 --exaggeration 10
--color-table template.kwl --srs EPSG:4326 input.src output.jpg

Example with color table without dot.src file:

ossim-chipper --op color-relief --azimuth 270 --elevation 45 --exaggeration 1.5 --color-table color-relief-lut.kwl --srs EPSG:4326 n37.dt1 t1.tif

Chipping examples in image space:

Chip about latitude longitude point, 512x512 in image space, rotate "up is up", histogram stretch, scale to eight bit, outputting to a png file.
Note the up is up mode requires a sensor model that is affected by elavtion.

ossim-chipper --op chip -u --histogram-op auto-minmax --cut-center-llwh -42.883986392005788 147.331309643650911 512 512 --scale-to-8-bit -w ossim_png 5V090205P0001912264B220000100282M_001508507.ntf up-is-up.png

Additional Parameters

ossim-chipper shares many of the parameters used in orthoigen including:

• writer-props
• resample-type
• thumbnail
• srs

It accepts a comma delimited list of input files or a .src file. The output file extension is used to determine output format. As with orthoigen, users can specify a writer to use with a -w argument.

SRC File

The src file used by ossim-chipper is nearly identical to the one used by orthoigen. The primary difference between the 2 is the use of the dem keyword to distinguish elevation data from imagery data. Example:

image0.file: C:\my_image.ntf
image0.entry: 2
image0.ovr: D:\support_dir\images\my_image.ovr
image0.rgb: 3,2,1

dem0:file E:\N38W123.hgt
dem0.entry: 0
dem0.ovr: D:\support_dir\dems\N38W123.ovr

dem1:file Z:\N37W123.hgt
dem1.entry: 0
dem1.ovr: D:\support_dir\dems\N37W123.ovr

Pan Sharpened Multispectral (PSM):

Example command:

$ ossim-chipper --op psm -b 3,2,1 --histogram-op auto-minmax --cut-center-llwh -42.902358775406725 147.337399071900336 256 256 --resample-filter sinc --scale-to-8-bit -w ossim_png 5V090205M0001912264B220000100072M_001508507/Volume1/5V090205M0001912264B220000100072M_001508507.ntf 5V090205P0001912264B220000100282M_001508507/Volume1/5V090205P0001912264B220000100282M_001508507.ntf outputs/psm-output-1.png

Inputs/outputs: