Hi Enrique,
In the OGC standard the start and end points of a simple polygon will be the
same point. So the azimuth will be 0. For a polygon containing rings it will
probably be the start point of the outer boundary and the end point of the last
ring, etc.. None of those is not going to be very helpful. Especially since the
start and end points of a polygon just tell you where the person chose to start
digitizing, which is not very meaningful in the real world.
How are you defining the azimuth of a dwelling?
I am assuming that the azimuth of the building polygon is the direction that
the front door of a building points towards?
If so, you might want to try finding the azimuth from the centroid of the
polygon and the end point of the shortest line from the centroid to the street
centerline segment that it is used for the street address, or just to the
nearest street centerline.
FYI, Building polygons don't usually have street addresses, so you may have
to get that from a spatial join with the parcel polygon, etc..
Give this some more thought and write back to the list if you still need help.
Please include what else you have tried and what results you have gotten.
-Thayer
On Monday, July 17, 2023 at 03:42:18 PM EDT,
[email protected] <[email protected]> wrote:
Date: Mon, 17 Jul 2023 19:15:18 +0200From: Enrique Sagredo Blanco
<[email protected]>
To: [email protected]
Subject: [Qgis-user] doubts about the azimuth value obtained
Message-ID:
<cakbdjwco3ng4ys4gr4yl_muryrkw4wngy--cyg90nt9jeic...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Good afternoon:
I am a professor at the University of Mondragon and for the research I am
carrying out I am using QGIS. I want to obtain the azimuth value of the
dwellings in a certain municipality, I have created a variable and using
code I have generated this function which I have attached.
degrees( azimuth( start_point( $geometry ), end_point( $geometry )))
The doubt arises when interpreting this data, since QGIS returns a value
but I don't know how to obtain it. Since it is a unique value, I don't know
how to interpret what it means on a map. Since the polygons analysed have
four sides.
Can you help me?
Thank you very much.
[image: image.png]
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