If you plot data from excl, maybe the problem is linked to the excl, in this case you need to convert angles from degrees to radiant, furthermore, excl reed the angles in a opposite direction with respect the wind chart, thus each angle value (alfa) should be transformed in 90-alfa before the conversion.
If you plot data from excl, maybe the problem is linked to the excl, in this case you need to convert angles from degrees to radiant, furthermore, excl reed the angles in a opposite direction with respect the wind chart, thus each angle value (alfa) should be transformed in 90-alfa before the conversion.
I don't know about ArcGIS 9.3, but in 10.3 following the blog works perfectly for displaying direction from u and v in a table. You could display the arrow size as the magnitude (100 * Sqr ( [u] * [u] + [v] * [v] )) --- 100 just for sizing, so it's visible on my display with my specific numbers. The only drawback, you can't display in color. For graduated color display you'd need the value of magnitude and direction in your table. I calculated the direction using field calculator as shown in the jpg when field calculator opens the parser is defaulted to VB script (no atn2() available), you need to click the radio button to Python, then you will find the Atn2() function (and a pi function as well --- see jpg) In case you can't see the jpg: direction = (180 / math.pi) * math.atan2( !u!, !v! ) Note: the result will be positive (for u>0) and negative (for u<0) values for direction. If you want to display current your arrow symbol needs to point up before applying rotation by direction (so either choose a symbol that points up or rotate any symbol by "angle" so it points up before applying the rotation by direction.
I don't know about ArcGIS 9.3, but in 10.3 following the blog works perfectly for displaying direction from u and v in a table. You could display the arrow size as the magnitude (100 * Sqr ( [u] * [u] + [v] * [v] )) --- 100 just for sizing, so it's visible on my display with my specific numbers. The only drawback, you can't display in color. For graduated color display you'd need the value of magnitude and direction in your table. I calculated the direction using field calculator as shown in the jpg when field calculator opens the parser is defaulted to VB script (no atn2() available), you need to click the radio button to Python, then you will find the Atn2() function (and a pi function as well --- see jpg) In case you can't see the jpg: direction = (180 / math.pi) * math.atan2( !u!, !v! ) Note: the result will be positive (for u>0) and negative (for u<0) values for direction. If you want to display current your arrow symbol needs to point up before applying rotation by direction (so either choose a symbol that points up or rotate any symbol by "angle" so it points up before applying the rotation by direction.
Sorry if this question comes late as this questions should be solved months ago. I have installed MGET, but I cannot find the python script to get the mag/direction, where is it please? Thanks!
Sorry if this question comes late as this questions should be solved months ago. I have installed MGET, but I cannot find the python script to get the mag/direction, where is it please? Thanks!
Try MGET tool http://mgel.env.duke.edu/mget/ . It has a python script to get mag/direction vector from u v vector component rasters. Hope this solves your problem
Try MGET tool http://mgel.env.duke.edu/mget/ . It has a python script to get mag/direction vector from u v vector component rasters. Hope this solves your problem
See this page (https://marinedataliteracy.org/ops/ss_height/ss_height.htm) for mapping of SSHa and geostrophic current magnitude and direction.
See this page (https://marinedataliteracy.org/ops/ss_height/ss_height.htm) for mapping of SSHa and geostrophic current magnitude and direction.
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If you plot data from excl, maybe the problem is linked to the excl, in this case you need to convert angles from degrees to radiant, furthermore, excl reed the angles in a opposite direction with respect the wind chart, thus each angle value (alfa) should be transformed in 90-alfa before the conversion.
If you plot data from excl, maybe the problem is linked to the excl, in this case you need to convert angles from degrees to radiant, furthermore, excl reed the angles in a opposite direction with respect the wind chart, thus each angle value (alfa) should be transformed in 90-alfa before the conversion.
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How can I plot U and V wind vectors in ArcGIS 9.3
How can I plot U and V wind vectors in ArcGIS 9.3
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I don't know about ArcGIS 9.3, but in 10.3 following the blog works perfectly for displaying direction from u and v in a table. You could display the arrow size as the magnitude (100 * Sqr ( [u] * [u] + [v] * [v] )) --- 100 just for sizing, so it's visible on my display with my specific numbers. The only drawback, you can't display in color.
For graduated color display you'd need the value of magnitude and direction in your table. I calculated the direction using field calculator as shown in the jpg
when field calculator opens the parser is defaulted to VB script (no atn2() available), you need to click the radio button to Python, then you will find the Atn2() function (and a pi function as well --- see jpg)
In case you can't see the jpg: direction = (180 / math.pi) * math.atan2( !u!, !v! )
Note: the result will be positive (for u>0) and negative (for u<0) values for direction. If you want to display current your arrow symbol needs to point up before applying rotation by direction (so either choose a symbol that points up or rotate any symbol by "angle" so it points up before applying the rotation by direction.
I don't know about ArcGIS 9.3, but in 10.3 following the blog works perfectly for displaying direction from u and v in a table. You could display the arrow size as the magnitude (100 * Sqr ( [u] * [u] + [v] * [v] )) --- 100 just for sizing, so it's visible on my display with my specific numbers. The only drawback, you can't display in color.
For graduated color display you'd need the value of magnitude and direction in your table. I calculated the direction using field calculator as shown in the jpg
when field calculator opens the parser is defaulted to VB script (no atn2() available), you need to click the radio button to Python, then you will find the Atn2() function (and a pi function as well --- see jpg)
In case you can't see the jpg: direction = (180 / math.pi) * math.atan2( !u!, !v! )
Note: the result will be positive (for u>0) and negative (for u<0) values for direction. If you want to display current your arrow symbol needs to point up before applying rotation by direction (so either choose a symbol that points up or rotate any symbol by "angle" so it points up before applying the rotation by direction.
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How can I plot U and V wind vectors in ArcGIS 9.3
How can I plot U and V wind vectors in ArcGIS 9.3
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VOTE
Sorry if this question comes late as this questions should be solved months ago. I have installed MGET, but I cannot find the python script to get the mag/direction, where is it please? Thanks!
Sorry if this question comes late as this questions should be solved months ago. I have installed MGET, but I cannot find the python script to get the mag/direction, where is it please? Thanks!
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What is the script to get wind speed from u and v data?
What is the script to get wind speed from u and v data?
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Try MGET tool http://mgel.env.duke.edu/mget/ . It has a python script to get mag/direction vector from u v vector component rasters. Hope this solves your problem
Try MGET tool http://mgel.env.duke.edu/mget/ . It has a python script to get mag/direction vector from u v vector component rasters. Hope this solves your problem
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may be you can use Surfer software. its better than Arc GIS for plotting U and V wind .
may be you can use Surfer software. its better than Arc GIS for plotting U and V wind .
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