This is a difficult question... There are 2 different questions here. 1 is like understanding how accurate data is (like scale, accuracy, etc.). The other is really how good is the data. This is just one more example of why there is more to mapping than meets the eye. First of all, over time, you start to understand what data is worth paying extra for, which is not. Many files are really govt. files, that everyone pretty much has the same accuracy and source. Not much difference between products - some usablility differences, but pretty similar. Some things, however, you shouldn't skimp on. I've been selling this stuff for several years now, and I pretty much know what things not to skimp on, but where possible, I try to save my customers money. ZIP Codes, for example. I only sell GDT ones. Why? Because it really takes alot to build these things. I've had other vendors try to have me rep their files, but I won't do it. This is complicated stuff. BE AWARE: None of this stuff is perfect. You're going to find errors in all files. This takes alot of time to understand and fix. But you'll start to see who really adds value and who doesn't. Good luck! -----Original Message----- From: Bill Thoen <[EMAIL PROTECTED]> To: Derek Wilson <[EMAIL PROTECTED]> Cc: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Friday, February 12, 1999 11:20 AM Subject: Re: MI Re: Just how accurate is that data we spend our money on? >This is what metadata is for. If a vendor's data doesn't include >it, then the data's probably not worth very much. Metadata is >"data about data", and it includes information about accuracy, >resolution, sources, processing performed and so on. The >information should be sufficient for you to make a reliable >estimate of the data's suitability to your needs. MapInfo >provides support for metadata, and data products like StreetWorks >and some others come with it. Unfortunately, there's precious >little info about metadata in the MapInfo manuals, but there's >lots more on the subject at: >http://www.fgdc.gov/metadata/metadata.html. There's also a couple >of freeware utilities (metadata.zip and Compass.zip) at the >MapInfo-L FTP site. > >- Bill Thoen > >Derek Wilson wrote: > >> Hi, does anyone have any warnings, comments or concerns >> regarding data purchased from a vendor. The last postal code >> point file I purchased had numerous duplications of lat and >> long values and a number of points were simply not in the right >> location. When I contacted the vendor to complain, they tried >> to downplay the inaccuracies. > >---------------------------------------------------------------------- >To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put >"unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED] ---------------------------------------------------------------------- To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
