I'm guessing the 1000 has the ability to input known elevation points? My 500 does. You can find the location of the NGS Benchmarks and input precise elevation points into the Garmin (find the point on the website, , or the better-than-nothing option, use the What is my elevation website to put in your approximate elevation. This helped quite a bit with my 500, as I found that on out and back routes, I was always descending markedly less than I was climbing or vice-versa.