ArcMap is run using primarily Shape Files and in more recent versions Geodatabases can be used to store larger sets of data. These file formats are what are uploaded into the program to view spatial data.
Edema is swelling of both legs from a buildup of extra fluid. Prolonged standing or sitting, especially in hot weather, can cause excess fluid to accumulate in the feet, ankles and lower legs. Tiny valves inside the veins of the legs can become weakened, causing a common problem called venous insufficiency.
Excess fluid can build up in various locations in your body, leading to a condition called edema. Edema is swelling that usually occurs in the feet, ankles and legs (where it's called peripheral edema), but it also can occur in the lungs (where it's called pulmonary edema) and in the abdomen (where it's called ascites).