B&G Deckman - Manual (Page 140)

Making wind or current Grids
9.13
Group Allows you to draw a rough circle around a number
of nodes (start and finish of the line are assumed to
connect). This selects all the nodes contained
within this area (they turn yellow). Clicking on any
of these nodes then allows you to scale speeds by a
factor, input a rotation or delete all the selected
nodes (see examples below).
It is advised that you use Save Nodes frequently when developing
forecasts so that you can easily revert to a previous version if later
changes do not work. The main purpose of the make Grid feature is to
enable you to input your own predictions in a format that Deckman can
use in its routing facilities. To do this, you develop a forecast for a
certain time. When you are happy with your forecast map, click
Actions>Save to Grid. Enter a file name followed by Save. You will
then be prompted to enter a date (format yymmdd) and time (hhmm) to
be associated with this forecast. You then develop further forecast maps
for later times, click Actions>Save to Grid. This time, select your
previously saved file followed by Save. This time, as well as entering
the date and time to be associated with the new data, you will also be
asked to select Overwrite (which replaces the existing data in the
selected file with your new data) or Append (which adds your new data
after the existing).
Note. Once you have chosen the Save to Grid option, you are unable to
manipulate the data in the forecasts directly. However, if you use GRIBs
in routing (see GRIB routing below) then there are a few additional
controls.
At all times when using the make Grid feature a box in the top left
corner of the navigation display shows the conditions at the present
position of the cursor.
As can be seen in the examples below, the distance between the
positions of the nodes is as important as the speed/direction at the nodes
themselves. This is because of the way Deckman triangulates between
the nodes for interpolation. As a general rule, it is best to have a closer
gap between successive nodes within 'lines' (when drawing a line, as in