Delagina:
You’re being kinda vague. Is the site half way around the world from you, or is it in the same general area as you are? USGS quadrangle maps show general contours down to at least a couple foot intervals in much of the US, and other areas too. Go to your city/county engineer and ask for the street or manhole cover elevation in front of the property, and what the local datum is for that survey. We’ve become so dependant on the internet in the last few years, that they are going to have to put a fart button on all cell phones or we are all going to be in big trouble.
allows that information to be extracted. It is based on the USGS topo maps, i believe. One known issue is that generally, it is the elevation of the "unimproved" landscape, and won't reflect bridges, road cuts, etc.
I do have old state atlases (paper) that show topo maps with a couple of hundred feet between lines.
If you're after flood planes, the city hall may have maps showing that already.
If you're after snow information, try the topo maps or check at city hall.
Good question
I have struggled with this also. Several municipalities base their snow loads on elevation.
Best I have been able to do is similar to what JStephen suggested- I have looked on line for topo maps for areas where this comes into play. Not always easy to find. If someone knows of a better way, I too am interested.
Not sure how accurate they are, but the GPS unit in my car reports the elevation and seems to update pretty frequently as the grade changes. If you want any accurate, reliable elevation then you should hire a surveyor.
GPS elevation is typically worse than position, expect about a factor of 2-ish worse than position error for any live GPS result.
Full GPS metadata can be post-processed to improve accuracy in the continental US with correction software if you have a typical Trimble or Magellan GPS.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!
