Star Hydro analysis starts with loading of terrain maps.
Layers required to perform analysis are:
Projected terrain
Pit filled terrain
Flow accumulation
Flow direction (D8)
Star Hydro at this time (7/9/2007) assumes that all layers coordinates are in meters.
At this time it is suggested to place files in:
$HOME/starhydro_workspace/StarHydro and load them using "File->Open->StarHydro".
On Windows XP folder is usually:
c:\documents and settings\(your user name)\starhydro_workspace
On Mac OS X and Linux it is:
/home/(your user name)/starhydro_workspace
I'm working on File manager that will make this easier.
USGS seamless map can be converted to Star Hydro using Arc Workstation using following scripts:
Gridname is the name of the grid in the Arc Workstation's workspace
Projectionfile is the file describing input paramters and output units (ZUNITS METERS, UNITS METERS).
%% Project using projection file from below
project grid gridname projected projectionfile
gridascii projected projected.xyz
%% Pit filling using ESRI fill method
grid
fill projected filled sink
quit
gridascii filled filled.xyz
%% Calculate flow direction
grid
flowdir = flowdirection( filled )
quit
gridascii flowdir flowdir.xyz
%% Calculate flow accumulation
grid
flowacc = flowaccumulation( flowdir )
quit
gridascii flowacc flowacc.xyz
---
%% To find original grid projection parameters use:
describe gridname
Sample projection parameters (projectionfile.prj):
INPUT
Projection GEOGRAPHIC
Datum NAD83
Zunits METERS
Units DD Spheroid GRS1980
PARAMETERS
OUTPUT
PROJECTION UTM
DATUM NAD83
ZONE 18
ZUNITS METERS
UNITS METERS
PARAMETERS
END
