[postgis-users] PostGIS Geography and Rhumb Lines

Derek Meyer derek at meyerprofessional.com
Wed Nov 28 01:39:09 PST 2012

My current project involves creating a spatial database of world-wide
airspace data, where each known flight information region is a polygon
containing boundaries that are a combination of great circle lines,
rhumb lines, and arcs.

It seems straight forward enough that these polys could be easily
inserted into the database via ST_GeographyFromText fed with a WKT
GEOMETRYCOLLECTION of these compound boundary types, but I'm wondering
about how to deal with rhumb lines in such a case since the Geography
functions, if I understand correctly, base everything around a round
earth model and utilize great-circle by nature.

Is there any way to explicitly declare a rhumb line in an insert query
such as this?  I've seen some examples elsewhere where a temporary
projection to 2D is utilized and then segmentized to
render/interpolate coordinates for a linestring that would more
accurately represent said rhumb line.  Is this still the accepted
approach?  Practical?  If so, how would such an approach be
implemented in context of the SQL query?

Any info/suggestions welcome and appreciated.

Thank you for your time,

- Derek

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