I've been tinkering with a street track in my hometown but Earth has awful height data. I can tell that where i live is not 6 meters above sea level, closer to 16 or more. Resolution is also way off, the local area is geographically very flat but it does have contours. The online kml height filler puts my track to -9999m. Any ideas how i can map these myself using basic surveying technics and/or GPS since there's no way i'm buing topographic maps of the area.