User:Jcreer/Direction Conventions and Conversions: Difference between revisions
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:Oceanographic = 90.0 - Cartesian (add or subtract 360 if out of range) | :Oceanographic = 90.0 - Cartesian (add or subtract 360 if out of range) | ||
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(Note: A definition for the first three can be taken from : | (Note: A definition for the first three can be taken from : | ||
https://www.xmswiki.com/wiki/Template:Angle_Convention) | https://www.xmswiki.com/wiki/Template:Angle_Convention) | ||
Revision as of 19:23, 9 December 2021
SMS supports the following direction conventions:
- Cartesian:: Add definition
- Meteorologic: Add definition
- Oceanographic: Add definition
- Shore Normal: "TO" convention based on a Theta(grid) which defines the grid orientation relative to the positive X axis (CCW direction). So:
Theta(grid) Direction of I axis
0 East
90 North
180 West
270 South
For a shore normal grid, the direction angle is interpreted as relative to the I axis with CCW as positive. Therefore, if Theta(grid) is 0 degrees (I axis aligned with X axis) then:
0 To the east
45 To the north east
-45 To the south east
When SMS converts from one convention to another the conversions always goes through Cartesian. For example, to convert from Oceanographic to Meteorologic, SMS converts from Oceanographic to Cartesian, and then from Cartesian to Meteorologic.
The conversions that are:
- Cartesian = 90 - Oceanographic
- Cartesian = 270.0 - Meteorologic
- Cartesian = ShoreNormal + GridOrientation
- Meteorologic = 270.0 - Cartesian (add or subtract 360 if out of range)
- ShoreNormal = Cartesian - GridOrientation (add or subtract 360 if out of range)
- Oceanographic = 90.0 - Cartesian (add or subtract 360 if out of range)
