# [postgis-users] Angle

Ezequias Rodrigues da Rocha ezequias at recife.pe.gov.br
Fri Jul 7 05:19:12 PDT 2006

```Now it is working perfect. Thank you Eduardo. Point finish. The X axis
here is not the same azimuth North axis and we only must to make some
changes to see the angle.

Thank you so much one more time.

ps: The image is perfect. You  must post it on the wikipedia too.

Regards
Ezequias

Eduardo Luís Garcia Escovar escreveu:
> Ezequias Rodrigues da Rocha escreveu:
>>
>>
>> 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:
>>>>
>>>>
>>>> Whre 1 rad = 57.29577951
>>>>
>>>>
>>>> Some features works someothers dont.
>>>> :-) :-(
>>>>
>>>> Regards
>>>> Ezequias
>>>> _______________________________________________
>>>> postgis-users mailing list
>>>> postgis-users at postgis.refractions.net
>>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>> Ezequias,
>>>
>>> You should have done like Marco said:
>>>
>>>
>>> Remember, this result is the azimuth (angle from the north, i.e.,
>>> from the y axis, clockwise).
>>>
>>> Hope this helps,
>>> Eduardo
>>> _______________________________________________
>>> postgis-users mailing list
>>> postgis-users at postgis.refractions.net
>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>
>> 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,
>
> I didn't understand what you meant by "from up to down". Watch the
> picture in attached file, so you can see what is the meaning of the
> azimuth function result.
>
> Regards
> Eduardo
>
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>

--
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"

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