Program updated on September 7, 2012. List of updates is given below.
The mb_out_nav program is a simple interface between MB System and GDAL/OGR. The program is used to export multibeam navigation from MB System to a multi-segment vector file supported by GDAL/OGR. Each segment of the exported multibeam navigation is tagged with the following attributes:
- multibeam filename
- julian day
- line length in seconds
- line length in kilometres
When imported into a GIS the vector attributes can be queried and used to control vector display. For example:
- to display all lines segments greater than 1.5 km in length
- to display all lines segments from Julian Day 126
The GDAL/OGR library allows output to a number of different vector formats. The formats currently supported by mb_out_nav include:
- ESRI Shapefile
- MapInfo TAB and MIF formats
- GoogleEarth KML
- Generic Mapping Tools (GMT)
- Geography Markup Language (GML)
The output format is automatically determined from the output file extension. For example output.kml will use the GDAL/OGR KML driver.
The program uses the GDAL projection functions to re-project the exported data if required. It accepts projection arguments in any of the formats supported by GDAL. This includes EPSG, proj strings, and WKT. For more information on accepted projections formats, check the GDAL utilities pages.
The mb_out_nav can be run from the command line with the following arguments:
mb_out_nav -i mb_datalist -o output_vector -n navigation_channel -p projection_info -f -e
mb_datalist is the MB System compatible data list made up of multibeam filenames, and their associated format
output_vector is the name assigned to the output vector file. The file extension determines the output vector format.
navigation_channel [optional] is the navigation channel number to export.
projection_info [optional] is the GDAL supported string for re-projecting the navigation before saving.
-f with use the fast navigation file (.fnv) if it is available [Note: this flag will override the -e flag].
-e will use navigation edit file (.nve) if it is available.
The individual multibeam filenames are printed to stderr as they are read.
The following examples provide various options for creating a navigation vector from a MB System data list entitled datalist.txt.
mb_out_nav -i datalist.txt -o navigation.kml
mb_out_nav -i datalist.txt -o navigation.shp
MapInfo MIF Re-Projected to UTM Zone 8N
mb_out_nav -i datalist.txt -o navigation.tab -p EPSG:32608
Download the gzipped tar file here.
Extract the tar file.
The mb_out_nav program is suppled with source code and a Makefile. No pre-compiled binaries are available at this time. The program requires the GDAL development files and the installed MB System.
To build the program edit the Makefile and set the prefix to the location of your installed MB System (e.g. /usr/local/mbsystem) and run make. Run make install (may need root privilege) to install the program in the MB System bin directory.
If nedCDF is not installed in a standard location you may have to set the directory in the in the Makefile. To set the netCDF location edit the Makefile and add the full path to the LIBS line with a "-L" flag (e.g. -L/usr/local/netcdf-4.1.3/lib).
- More testing and debugging.
Add support for reading MB navigation edit (.nve) files.
Add support for reading MB fast navigation (.fnv) files.
- Add additional vector formats.
- Add additional vector attributes such as start and stop times.
- Add vector attributes for project and folder names.
- Add support for exporting soundings (wkbPoint).
- Probably lots more...
(Updated on September 7, 2012)
- Added a new -e flag to read navigation edit file if is available. It it is not available, the program fall back to the original raw file.
- Added a new -f flag to read fast navigation file if is available. It it is not available, the program fall back to the nav edit file (-e) or the original raw file.
- Changed the name of the source directory (and tar filename) to match name of executable.
- Minor code cleanup.
(Updated on July 4, 2012)
- Added math lib (-lm) to LIBS in Makefile
- Changed Filename attribute to Name for improved display in GoogleEarth (KML)
Thanks to Gordon Kieth for Bugfix and Comments.