Alternatively, you can use your cell phone's mapping app (i.e. Google Maps) to find the latitude and longitude.
To do this, once you are at the dumping site, you can:
STEP 1: Drop a pin.
STEP 2: Locate the latitude and the longitude (it either pops up automatically or you can right click on the pin).
In this sample screenshot, the first number (32.308549) is the latitude and the second number (-90.205599) is the longitude.