User:Jcreer/Direction Conventions and Conversions: Difference between revisions
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(Created page with "__NOINDEX__ SMS supports the following direction conventions: Cartesian:: Add definition Meteorologic: Add definition Oceanographic: Add definition Shore No...") |
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__NOINDEX__ | __NOINDEX__ | ||
SMS supports the following direction conventions: | SMS supports the following direction conventions: | ||
Cartesian:: Add definition | |||
Meteorologic: Add definition | :Cartesian:: Add definition | ||
Oceanographic: Add definition | :Meteorologic: 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: | :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 | Theta(grid) Direction of I axis | ||
0 East | 0 East | ||
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180 West | 180 West | ||
270 South | 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 | 0 To the east | ||
45 To the north east | 45 To the north east | ||
-45 To the south 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 | |||
ShoreNormal | :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) | |||
<-- | |||
(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) | ||
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- enter 0, 25, 1, 1 in the parameters table | - enter 0, 25, 1, 1 in the parameters table | ||
At this point the picture in the upper right corner of the dialog displays the direction. You can change the convention to see samples of the images I am talking about) | At this point the picture in the upper right corner of the dialog displays the direction. You can change the convention to see samples of the images I am talking about) | ||
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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)
<-- (Note: A definition for the first three can be taken from :
https://www.xmswiki.com/wiki/Template:Angle_Convention)
(Note: It would also be good to have some images to illustrate. You can see an idea of this by doing the following:
- create a new spectral coverage
- create a point in the coverage
- double click on the point to bring up the spectral energy dialog
- click "Create Grid" and click OK two times to get a grid
- click "Generate Spectra" to bring up the Generate Spectra grid
- enter 0, 25, 1, 1 in the parameters table
At this point the picture in the upper right corner of the dialog displays the direction. You can change the convention to see samples of the images I am talking about)
-->
