Altitude

It is possible with some diligent web work to find the elevation of any spot in the US, and many spots in the rest of the world. Microsoft's Terraserver has aerial maps of the entire US and spotty maps of Europe. Using this, you can zoomed in and literally find your house. You can then find the latitude and longitude of that spot to within less than a second of accuracy by clicking on 'Image Info'. If you are in a covered area, you can get a not-bad elevation reading by clicking on 'Back' then on 'Topo' from there. The scale is different, so it might be a little tricky finding your point. By reading the contours and finding your spot on the map, you can come fairly close to the correct elevation. If you are in an area not covered by the terraserver, find your latitude and longitude as accurately as possible, to less than a second if possible. And be prepared to do a lot more work.

The US Geological Survey has topographical maps called DEM files (digital elevation models). Finding the right one is a bear so they have a guide. The files can be large, and the data files are usually zipped and tar'd (double compressed) but when you find the right one and get it uncompressed, you're in business. They are available for free by anonymous ftp. Using the freeware program called MICRODEM, you load the DEM file, zoom in, and as you move the cursor around, the latitude, longitude, and elevation are displayed for any point on the map. If you have hills around, you can actually recognize the terrain using perspective views.

Offered by George.

Here is a link to a convenient website that people can use to put in their Geographical Location to determine their height above or below Sea Level. For instance, for Philadelphia, PA, my hometown.

Offered by Dave.