> On Oct 10, 2015, at 3:06 PM, Even Rouault <even.roua...@spatialys.com> wrote: > > Le samedi 10 octobre 2015 13:45:05, Dimitrianos Savva a écrit : >> Hi all, >> >> Recently I noticed that the ExportToWKT >> <http://gdal.org/java/org/gdal/ogr/Geometry.html#ExportToWkt()> function >> of a Geometry object that has been read from a Shapefile, generates the >> well known text representation without any compromise on the precision of >> the coordinates values. >> >> I wonder how these coordinates are represented in memory. A double >> precision floating type is not enough to represent some coordinates. >> >> For example the geometry POINT (4799826.09861662145704 >> 2773995.445373429451138) cannot be represented by two double types. But >> still the ExportToWKT function produces the correct result with full >> precision for the values. > > Dimitrianos, > > The implementation of ExportToWKT() in GDAL uses 15 decimal figures ("%.15f" > printf formatting) whatever the source precision was, and as you point, > whatever the intrinsic precision of the double value is. > > Even > > -- > Spatialys - Geospatial professional services > http://www.spatialys.com <http://www.spatialys.com/>
Thanks you for the quick answer! Actually I was confused at some point, because some geometries had the exact precision as in the Shapefile, and some other not. Thanks again, Dimitrianos
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