i want to find out the slope grade of some small hills near my house, i don't know how. Any sites with maps that shows the grade of each hill? i heard google maps does this, but i don't see it.
This is likely a reference to the Google Earth tab in google maps. The program Google Earth itself is worth a look too; you move your cursor over a spot on the map and it shows a pretty close estimation of the elevation.
Back in the day. I used topozone - counted the contour lines and used a ruler to measure distance. Not technically accurate on steep slopes, but close enough. I found all the best hills in my state that way. Then the site got bought out and they charged a fee to view the maps.
Sadly a feature missing from many online maps for the first 10 years or so. I'm not sure how google maps got popular without it. Bing maps can switch to ordnance survey maps. They have contour lines and view points labeled. I use there land ranger maps whenever possible. The tools above are a lot more use to the op though, now that they exist.
I started using Bikely.com back in 2010, although after a few months the servers were becoming troublesome. Then I switched to MapMyRide.Com - which has already been suggested. So for that trip to Cali in 2010... I used the first service, and the second was used for 2011.
About two years ago I worked on a project for a client where I integrated ArcGIS APIs into their user interface (UI) and then I began to understand how easy it is to create your own application. For the pedestrian, unless you're into writing code this task will be overwhelming. Although I think any freshman at programming could figure it out and achieve decent functionality.