Hello Philip, When a file is specified as Longitude/Latitude only, with no datum listed like your example, Longitude/Latitude (NAD83), it means that the datum is undefined. If you know the source of your data you may be able to trace back the original datum that the data was based on. If not, then you might run into difficulty trying to make assumptions about the datum and the accuracy of your data. It may very well be NAD83, but it might also just as easily be NAD27 or something else, each of which would have different levels of accuracy when compared to another datum. I'd suggest trying to trace it back to the source first. Good luck!
Regards, Sam Knight Applications Specialist Blue Marble Geographics [EMAIL PROTECTED] Ph: 800-616-2725 ext. 24 Ph: 207-582-6747 ext. 24 Fax: 207-582-7001 http://www.bluemarblegeo.com and http://www.beyondgeo.com ---------- Original Message ---------- FROM: [EMAIL PROTECTED] TO: MapInfo-L@lists.directionsmag.com DATE: Mon, 18 Apr 2005 08:35:10 -0500 SUBJECT: MI-L Projection Education Question Group, Quick question about projections with MapInfo. We have some tables with the projection of "Longitude/Latitude" under the Category "Longitude/Latitude" and then some with "Longitude/Latitude (NAD83)". Is there a difference and if so, how large. 10 feet? thanks -------------------------------------------------------------------- Philip Lesnik Research Systems Analyst, Market Research General Growth Properties, Inc. 110 N. Wacker Drive BSC 3-13 Chicago, IL 60606 312-960-2998 312-960-5519 (fax) [EMAIL PROTECTED] -------------------------------------------------------------------- ----------------------------------------- +++++++++++++++++++++++++++++++++++++++++++++++++++++++ Notice: This e-mail including attachments) is covered by the Electronic Communications Privacy Act, 18 U.S.C. ~~ 2510-2521, is confidential and may be legally privileged. If you are not the intended recipient, you are hereby notified that any retention, dissemination, distribution, or copying of this communication is strictly prohibited. Please reply to the sender that you have received the message in error, then delete it. Thank you. +++++++++++++++++++++++++++++++++++++++++++++++++++++++ --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 16132 --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 16133
