gge n ggp advocate thanks to workers blowout, page-22

Thanks hitnmiss43 - coincidentally last night I finally got a quiet window to spend some time with the Louisiana GIS and found the exact thing you referred to and also lots of other interesting stuff. Its a fascinating resource that repays a few hours of investigation and I regret not taking your hints much earlier. :-)

What surprised me quite a bit was the number of documented wells within a stone's throw of ours - well, maybe a bit further! And when you zoom out to a state view there's just a huge cloud of them - I guess I knew that from the database listing but the visual presentation really brings it home!

I also spent some time learning a bit more about the NAD-27 SPCS and the NAD 83 geographic coordinate systems used by SONRIS and how to move between them - pretty complex stuff with lots of tricky details that need to be understood. I'm also keeping an eye out for WGS 84 which is what Google Earth uses. I was surprised that some of the conversion didn't just need complicated equations for conversion but actually needed iterative numeric solutions with careful control of errors and so forth to ensure they converge!

I tried lots of Excel addins but I think I've finally found what I need in the form of a DLL (there are several commercial products of course but this one has an evaluation version that just puts up a splash screen) that can do the required conversions.

I guess it's unnecessary for me to understand all this stuff in detail really but I enjoy learning new stuff so when life throws up conundrums I tend to dabble a bit until I get an overview. I guess I use this like some people use crosswords!