Re: [boost] geodetic library

Subject: Re: [boost] geodetic library
From: Michael Fawcett (michael.fawcett_at_[hidden])
Date: 2009-08-28 09:53:25

On Fri, Aug 28, 2009 at 4:38 AM, Barend Gehrels<barend_at_[hidden]> wrote:
>
> Michael Fawcett wrote:
>>
>> Do you have plans to support WGS84? Â What about Vincenty?
>>
>
> GGL has Vincenty distance calculations but you probably mean transformations
> here?

I meant distance as well as "destination point from a start point,
bearing, and distance".  We currently use ESRI for all of our GIS
needs, but GGL looks like it can start slowly becoming a replacement
for certain areas of our work.

One thing that I haven't seen in either library is offsetting a
polyline (linestring).  Something like this:

http://resources.esri.com/help/9.3/ArcGISEngine/arcobjects/esriGeometry/esriConstructOffsetEnum.htm

The reason I ask is because ESRI has a nice little note in their documentation:

"This [sic] results produced by this method are sensitive to large
offset distances, particularly when the offset distance is larger than
the length of the segments in the reference geometry.  The remove self
intersecting arcs feature is particularly problematic when extremely
large offsets are involved. "

And, indeed, that is the case.  The results start to go nonsensical
once the offset distance is larger than the length of the segments in
the input polyline.

I'm hoping to give Boost.Polygon a try soon, as well as GGL.

--Michael Fawcett