Thanks to all that replied to this post! I think this gives me what I need for now. This application will have a Phase I, which is sort of a proof of concept. In this phase, there wouldn't yet be a graphical mapping component, but they would already be capturing some type of location information for assets.
What I've learned here is that capturing latitude and longitude up front will give the information much more leverage down the road. I will include these fields in addition to some generic ability to capture basic textual location for people that don't know lat/long. But by making those fields visible now, and explaining their ultimate use, I expect the clients will be more than interested in deternining and entering them.
I will also go read some of those white papers at
www.esri.com. This is just what I wanted--to be able to know what is possible and how to plan for it, eben if we're not doing it for a few months.
One follow-up:
Is there some absolute maximum precision that these systems use? That is, if I include lat/long fields, do you have a recommendation of field size and decimals?
For example, if I look at info provided by the US census (
www.census.gov), most data is specified in 10^-6 degrees (millionths). OTOH, their Zip Code data has only decimal lat/long (which makes sense, since a Zip Code isn't a point). If I have less accurate data (like the client only knew the Zip), do these mapping engines have ways of dealing with that without assuming you know it's a specific point? (I'm guessing this would have to do with zooming in and out, but this guess is based on just seeing a few apps with mapping functions.)
OK, OK, I'll go read the white papers and stop asking questions that are probably all covered on Page 1 there <s>.
Regards,
-- Randy
>Randy,
>
>have a look at
www.esri.com. They are the marketleader for GIS software, a very informative site, a lot of white papers. They have activex controls for mapping, I haven't found the time to test them with vfp, but I hope in near future .... Their products use xBase type files for the GIS data. They also have a product to use it over the web, really great, on the website are links to a lot of other resources, including online demos.
>
>Contact me if you have any further questions.
