[postgis-users] Angle

[Ezequias Rodrigues da Rocha]

Eduardo Luís Garcia Escovar escreveu:
> Ezequias Rodrigues da Rocha escreveu:
>> marco vieira escreveu:
>>> Ezequias:
>>>  Look at postgis documentation. azimuth() returns radians, not 
>>> degrees. You must divide by pi rad and multiply by 180 degrees to 
>>> obtain 124,9 degrees. Make sure your azimuth is 143,9 by manual 
>>> calculation using start and end points (make sure you are using the 
>>> same start and end points).
>>> Regards.
>>> -- 
>>> Marco Vieira
>>> +55 21 9499-6800
>>> e-mail: maovieira at gmail.com <mailto:maovieira at gmail.com>   
>> Marco,
>>
>> I did the following:
>>
>> DesiredDegree = 180 - ColumnInRad /PI * 1 rad
>>
>> Whre 1 rad = 57.29577951
>>
>>
>> Some features works someothers dont.
>> :-) :-(
>>
>> Regards
>> Ezequias
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> Ezequias,
>
> You should have done like Marco said:
>
> DesiredDegree = ColumnInRad/pi( )*180
>
> Remember, this result is the azimuth (angle from the north, i.e., from 
> the y axis, clockwise).
>
> Hope this helps,
> Eduardo
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>
Thank you Eduardo,

Could you see for yourself.

My feature is this one:

MULTILINESTRING ((290635.73828125 9108941.88085938, 290635.94921875 
9108941.77929688, 290636.2890625 9108940.7109375, 290636.51953125 
9108918.06054688, 290636.509765625 9108917.55078125, 290636.119140625 
9108916.06054688, 290635.279296875 9108914.69921875, 290635.146484375 
9108914.5703125))


The angle my Desktop GIS application says is (OpenJUMP): *91.76 degrees* 
(from up to down)

The Azimuth generated by Postgis is:  3.16325843263936

The angle applying this formula (you suggested):  *181.241357699403 degrees
*

So what is wrong ?


Regards ...

-- 
Ezequias Rodrigues da Rocha
http://ezequiasrocha.blogspot.com
msn:ezequias at hotmail.com
"the worst of democracies is still better than the best of dictatorship"