Imagine a chart listing people in a shelter, supplies, or resources. Any of these resources can be moved graphically to any other location by any station in the net. No problem, just create one on the map, and manually move it as you talk to him on the radio. His postion will be shown on every APRS screen in the area in a matter of seconds. APRS has all the symbols for weather conditions, and each weather condition can be placed on the map for all to see.
Information is transmitted instantly to all other APRS stations.
New stations coming online can query other stations for known information, such as the locations of shelters, and hospitals. Another way that differentiates APRS from other packet programs is it's ability to pick information off the air passively. A very few stations can get information out to several hundred stations with only one or two transmissions. Other packet messaging systems require that each station recieve it's own unique copy of any given message. The maps available vary in detail from the entire world right down to the tables at a hamfest.