Startup files(optionals, but recommended)
The basic startup files (*.startup) contain some low level setting to accelerate the use of xscan in a given configuration:
- main geographical frame and pre-defined zooms sequence
- default geographical projection
- shorelines and bathymetry default files
- default working directory
An additional script file can be used to force higher level default settings.
Using/editing shoreline database:
There is a specific "shorelines" menu to load, display, edit and save Genesis shoreline binary files (*.cst). However, it is one of the oldest layer of Genesis that was written in Fortran, and is no more developed. It is strongly advised to limit the use of shorelines menu to load the *.cst files or import another format that will provide shorelines to the display and to the coastal line re-sampling routines.
The "segment edition (new)" menu, based on C/C++ is the place to import/export non-Genesis format and/or to manipulate the database.
We found the NGDC/NOAA gshhs release 2 to be very helpful for most of the coastal regions. You can either download directly the file from the gshhs web site (for versions up to 2.0), import it in "segment edition (new)" and save it at the binary Genesis format (*.cst).
We can also provide you with already converted gshhs files (release 2.0). For newer release, we are implementing the "shape" library (libshp) to deal with this format (needed for gshhs release 2.2).
Meanwhile, NGDC still provides the traditionnal (non-shape)binary format that you can load from xscan.
Using/editing topography database:
Bathymetry can be loaded, edited and saved from the "topography" menu". Native format in Genesis is the GMT well known format (*.grd). NetCDF file can also be used if bathymetry variable is named "bathymetry", "z", or "depth". See our link page to useful databases.
Geo-referencing of airborne/space views and other images:
The "legends and GIS" menu allows to geo-reference images and integrate them in the display. It can be very useful to create your own (precise) shorelines from Google Earth, Landsat, etc... views, view SST images in their geographical context etc...
xscan provides a lot of mesh editing/generation facilities. You first need to decide for a shoreline dataset, (you can re-sample it at targeted resolution from xscan) and bathymetry. Then set up the mesh resolution parameters, assembly the re-sampled shoreline segments to form mesh boundary descriptor. For boundary descriptor, let's recall that:
- first boundary MUST be external boundary
- if you use "island auto-detect" facilities, be aware that it will takes all (visible) closed segment as an island. If the external boundary is one-block closed too, slightly zoom inside or cut into 2 pieces. If you don't, it will appear twice in descriptor file, and spoil all the meshing process.