Introduction
Updated Version Released August 15, 2012 (see notes below)
The r.in.mb GRASS/Mb-Stystem program is designed to import mbio compatible multibeam data directly into the GRASS GIS.
The program is a modified version of r.in.xyz. Instead of reading an ASCII XYZ file, r.in.mb reads an MB-System compatible list file as shown below.
/data1/MULTIBEAM_DATA/RAW2007/07_Pingos_JD245_RAW/0050_20070902_154139_Petrel.all 56 1.0
/data1/MULTIBEAM_DATA/RAW2007/07_Pingos_JD245_RAW/0051_20070902_155508_Petrel.all 56 1.0
/data1/MULTIBEAM_DATA/RAW2007/07_Pingos_JD245_RAW/0052_20070902_161050_Petrel.all 56 1.0…
The r.in.mb program automatically projects the MB coordinates into the current GRASS coordinates. The program also does a simple in-fill (default = 3×3) on the imported GRASS raster. The in-fill routine is taken from the GRASS program r.grow.
The r.in.mb program uses the following new and changed command options from r.in.xyz:
Parameters:
input MB-System style list-file
width Restrict data by acrosstrack distance (Max)Flags:
-a Use amplitude (default = bathymetry)
-s Use sidescan (default = bathymetry)
The percent option of r.in.mb (xyz) allows large datasets to be imported when system memory is restricted.
Example:
Step 1:
Create MB-System style data list.Step 2:
Set GRASS region and resolution for importing multibeam data.Step 3:
Import bathymetry using …
r.in.mb inp=datalist.mb-1 out=mb_bathy_raster
Import backscatter using …
r.in.mb -a inp=datalist.mb-1 out=mb_backscatter_raster
Updated Notes: August 15, 2012
A new version of r.in.mb has been released with some new options and code cleanup. A GRASS 7 version is also now available. The new options include:
- length: allows the user to specify a minimum length for a multibeam file (default = 0.0). This allows shorter lines, such as turn lines, to be ignored during import.
- speed: restrict data by speed (min,max). If set, it will ignore all data outside of user specified range.
- min_beam: restrict data by minimum beam number (default = use all beams). All data less than minimum beam will be ignored.
- max_beam: restrict data by maximum beam number (default = use all beams). All data greater than maximum beam will be ignored.
- mode: (Simrad only) Restrict amplitude and sidescan gridding by only using pings collected in the user specified mode. Use mblist to obtain complete list of modes used during the survey.
A few options from the original r.in.xyz that are not used have been removed.
Building Source
or
- Download the GRASS7 source code tarball here
- Extract the tar file in GRASS source tree in raster directory.
- Change to r.in.mb directory and edit the Makefile. Edit the MB_INSTALL variable at the top of the file to set the installed location of MB-System.
- Run make to build program.
ToDo
-
Port program to GRASS v. 7 .done - Improve coordinate handling. Program assumes multibeam data is in geographic coordinates and re-projects to current GRASS coordinates.
- Improve data in-filling routine.
-
Add more gridding options such as
beam restriction, weighted beams, etc. -
Add program to directly import multibeam navigation as GRASS vector (for setting region and showing coverage). Done see mb_nav_ogr - Build stand-alone program that uses mbio and grids using something like the glib N-ary Tree. This would allow fast access to more complex gridding routines such as nearest neighbour.