Backscatter


Backscatter Data Processing Pipeline

Through measuring and processing the backscatter, we can get an idea of the type of sediment of the bottom. Caris only processes the raw backscatter, but the OMG software can make calculations to show the bottom backscatter better. In this paragraph we will explain how to process backscatter data with the OMG software, and which methods exist.


  1. First I will explain how to process backscatter
  2. I will explain how to put this the easiest way in ArcMap
  3. Another method is making a geotiff of the backscatter map, which can also be imported in ArcMap
  4. Finally I will explain how to show backscatter in ArcMap without importing backscatter from omg.


1. Process backscatter in OMG

When you set the unravel script to output ss, there will now be a directory called ss.. it will contain the raw backscatter data.. There are three different types as explained by JHC.. ss, ss_500 and ss_bp. You can now process either one and have a look at in in jview.. If your unravel script did not output ss, you can still run new_redoss by itself (new_redoss merged/*/*.merged).


2. Make a .mos

Normally we put the mos files in a folder called mos.

make_blank -boundsof merged/*/*merged
input same name (prefix) as used for DTM, I would use .bp for ss_bp, .roll for ss_500 and .ss for ss!!
use 8bit array
same mpp as in DTM

tomos prefix

mos2 ***.bp ss/JD***/*.ss

mos2 ***.roll ss/JD***/*.ss_500

mos2 ***.ss ss/JD***/*.ss_bp

jview prefix.mos


3.  Convert this file to ESRI

edhead -dump_geotiff  ***.8bit

r4toESRI -8bit_no_data 255 -real_8bit_range -108 20 -in  ../MOS/***.ss.mos -out ***.mos

r4toESRI -in ***.r4 -out ***.dep


4. Make a geotiff

stretchacres -low 140 -high 195 -in mos/JD121_sand.roll.mos -out temp.mos

mix_ci -ppm -monofil -i mos/harbour.mos -m harbour.ppm

convert harbour.ppm harbour.tif

edhead -dump_geotiff mos/harbour.mos

geotifcp -g mos/harbour.geo_meta harbour.tif harbour.geo.tif


5. Making backscatter in ArcMap

Is explained in the ArcMap section, under creating hillshaded grids.. link