David, I stand corrected on the significant digits used in TIGER. It seems there is a slight difference in unit specificity in the projection that I assumed versus what TIGER provides
4269 degree Unit = 0.01745329251994328 Tiger degree Unit = 0.017453292519943295 This threw off the retrieval calculation of the coordinates and didn't result in round numbers at the 6th decimal place and thus was calculated to the maximum significant digits of the library (15 digits). In regards to what I'm suggesting: I am simply suggesting that we use the standards that have existed for over a decade for the storage of geometrical data, namely Well-Known-Text or Well-Known-Binary. The reason I am suggesting this is because you've already submitted a desire to perform calculations that have been optimized under libraries that use WTK/WTB. The other reason that I am suggesting this is that latitude and longitude is not the only coordinate system that would benefit from using the standard. For instance, if someone has an RFID grid in their warehouse, they could benefit from the same conventions being used. In regards to "What about the other databases?": I can't imagine the other databases with spatial extensions would require approaches that were much different to benefit from GIS. PostGIS happens to be an implementation of the OGC standards, so databases that have an implementation of that standard would benefit from code written to that standard. The GeoTools Module Matrix plugins should give you an idea if you're concerned about connecting to other databases. http://geotools.codehaus.org/Module+Matrix David E Jones <[EMAIL PROTECTED]> wrote: Here is what I found in a quick search: "Coordinates in the TIGER/Line® files are in decimal degrees and have six implied decimal places. The positional accuracy of these coordinates is not as great as the six decimal places suggest." That is from near the bottom of page 6 of this document: http://www.census.gov/geo/www/tiger/tigerua/ua2ktgr.pdf Or are you referring to a different TIGER? BTW Chris, I'm having a lot of trouble understanding your posts. I don't know if others are running into the same thing, but much of the time I'm not sure quite what you're getting at or what you propose as many of these seem to be little snippets of thought instead of entire thoughts... could explain a little more of what you have in mind? Also: I looked at the postgis stuff you added, and... what's the point? If it only works with postgres how is that useful for OFBiz? -David On Jul 2, 2008, at 4:31 AM, Chris Howe wrote: > In addition, TIGER road data is to 15 significant digits as is US > data for county political boundaries. > > Chris Howe wrote: Roland wrote: Hi David, > > as I wasn't really sure about what to answer to your question, i > looked a bit > around: > http://geocoder.us/blog/2006/03/23/how-many-digits-are-enough/ > if their data is correct: 0.000001 degrees are 4.37184 inch or > 11.1044736 > centimeters > that ought to be enough for everyone ;-) > > seriously: I think for applications like mapping out addresses that > should be enough for years, but there may be other use cases i can't > imagine right now. > > --Roland > > 640K ought to be enough for anybody. This reminds me of another > benefit to WTK/WTB. WTK and WTB are not dependent on the coordinate > system you are using. Whether your coordinate system is the > latitudinal and longitudinal circles of the earth or whether they > are the coordinate system of your RFID enabled warehosue, WTK and > WTB handles them the same. Same data format, same use of > projections, same reliability in application you build. Why record > the same type of information in 15 different formats based on their > use? >
