Difference between revisions of "Digital Terrain Creator"

Revision as of 18:10, 23 February 2012

The Digital Terrain Creator is a small executable used to generate bathymetries from baseline data. Its inputs are a grid file(.grd) and an ascii xyz points file(.xyz)(or several bathymetry files for overlapping). Optionally a land polygons file(.xy) can be added in order to force land points. Its output is the bathymetry griddata file(.dat). The Digital Terrain Creator tool reads its option from the CreateBathymetry.dat file.

Options file

Here's what a CreateBathymetry.dat option file looks like:

!This is the output bathymetry file:
BATIM_FILE                  : GridData_2.dat

!This is the grid where the bathymetry will be created
GRID_FILE                   : ..\..\CostaPortuguesa12W36N_6p15W45NETV4.grd

!This is an initial bathymetry griddata file (optional)
!BATIM_INI                   : ..\..\CostaPortuguesa12W36N_6p15W45NETV3.dat
!MATCH_IN                    : 0
 
!Here lie the land polygons files
<BeginLandAreaFiles>
..\..\PortugueseLineCoast_new.xy
<EndLandAreaFiles>

!Here lie the baseline XYZ Points data files
<BeginXYZPointsFiles>
..\..\xyz\ET13W35N_5W46N.xyz
<EndXYZPointsFiles>

!Perform bathymetry smoothing within a specific radius
SMOOTH                        : 0 (1/0)
RADIUS                        : 0.05(dimensions of the grid file, for eg., degrees)
 
!Here is defined the interpolation method
INTERPOLATION               : Triangulation   !No Interpolation; Triangulation; Spline
 
!Here are the interpolation method options 
POINTS_FOR_INTERPOLATION  : 3
EXPAND_GRID_LIMITS        : 1
GRID_LIMITS_PERCENTAGE    : 0.25

Overlapping

To overlap several bathymetries, each one with a specific weight on the final bathymetry, add the following section to the options file. Overlapping requires an existent initial bathymetry and at least one bathymetry to overlap with.

Options file

BATIM_INI                   : Initial.dat    !the initial bathymetry
GRID_FILE                   : Initial.dat    !the grid (must be the same for the initial and others
BATIM_FILE                  : FinalFile.dat
OVERLAPPING                 : 1              !do overlapping
OVERLAPPING_NUMBER          : 1              !number of overlapping bathymetries

(Block for each overlapping bathymetries)
<BeginGridDataInfo>
LEVEL                     : 1
GRIDATA_FILE              : Overlap.dat      !the overlapping bathymetry
PERCENTAGE                : 1                !Fraction (0-1) of importance given to this Grid Data
	<<BeginAreaFiles>>
         overlap_area.xy                     !Path to the polygons files defining area of the
                                             !grid data file to be used. Each line defines one file
	<<EndAreaFiles>>
<EndGridDataInfo>

Interpolation methods

Triangulation

No Interpolation