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Hello FMEers,

 

 

I have run into a problem when trying to translate and reproject a file based circular buffer polygon feature class from UTM83-11 to LL83.

 

 

Background

 

- i have a workbench that takes project based circular buffer polygon feature class and translates it (ie. changes some attributes, add's some attribute values based on user paramaters) and then reprojects the polygon to LL83 to push into a central TQA geodatabase.

 

 

Problem

 

- Once the reprojection is finished the circular polygons appear to be flattened into and oval shape.

 

Is there a way to correct this so that the polygons maintain there geometric shape? Or is there no way around this when projecting to a geographic coordinate system. It is important for the polygon to maintain its shape because it is a buffer.

 

 

Thanks Evan
Hi,

 

 

My idea is: replacing the circular polygon with its center point before reprojection, and re-buffering the point after.
I think your problem is that UTM zones are so big and the origin is far away from your center so when you reproject to LL83 the feature gets projected.

 

Which is probably accurate.

 

 

You might try buffering in an equidistant coordinate system that has its origin closer to the center of the feature you are bufferering.

 

 

Reproject into an arbitrary equadistant coordinate system before buffering.

 

_AZMED_  works well for me.

 

Then project back into LL84.

 

 

If that doesn work then you could create a circular feature (Arc or Ellipse) (not buffering at all) and then when you reproject into LL83 stroke the Arc

 

 

Hey Evan,

 

 

You can use the GeographicBufferer in FME 2013 to fix the problem. It'll let you keep your data projected but give it a "geographic/LL83" style round buffer. 

 

 

 

--Matt

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