On Wed, 3 Mar 2004, Stanley K. Johnston wrote: > Does anyone know the level of accuracy of MapInfo vs. ESRI or other GIS > systems when it comes to surveying, specifically in the marine environment?
MapInfo's map coordinates are based on long integers, and the precision is based on dividing the distances between the map boundaries by about 2 billion. You can increase the precision by adjusting the boundaries. The nice thing about using integers (as opposed to using double-precision floating point numbers) is that integers can be manipulated faster and the results are not as prone to rounding errors. I believe that ESRI ArcGIS uses double precision floating point numbers to store coordinates. Either one will give you sub-centimeter precision. If you want the details, Jacques Paris wrote a rather good paper on the subject of precision in MapInfo (see www.paris-pc-gis.com/ppcc/intpreci.pdf.) - Bill Thoen --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 10698
