What Is GPS

Tools Geographers Use

Maps - Cartography, or map making, is one of the fields of geography.

Geospatial technology

GPS Global Positioning Systems GIS Geographic Information Systems

What is GPS? A network of satellites orbiting Earth that broadcast signals that can be picked up by receivers on Earth's surface.

How does it work? Receivers on earth get signals from satellites and calculate the distance from the satellites based on the time it takes to receive the signal.

What do we use it for? We monitor earthquake faults and volcanoes, tracking wildlife like birds and animals, tracking vehicles like police cars, ambulances, taxis, trucks, tracking people and pets too, of course for map making and navigation, and for recreation like geocaching.

Do you have GPS?

You probably do... Most phones have GPS, they use it automatically to keep the clock in your phone in perfect time.

GIS is another tool used by geographers. It is a powerful software program that creates incredibly detailed maps. It works by making maps in layers. We start with an empty map of an area and we can put ANYTHING we want on it- Maybe that is information about roads and houses, maybe we want to see how the natural landscape and the human landscape interact so we add a layer of floodplains or a layer of earthquake faults... Or maybe we want to know about how healthy people are or how much crime is in an area, or how many people go to college, or how much money people make... We can map all of those things and even more using GIS. There a GIS online or in apps called Google Earth, maybe you have used it?

We can turn layers on and off Google Earth and make a map of just what we want too. We use latitude and longitude to precisely locate places, see here that Google Earth has coordinates at the bottom...

Latitude and Longitude- a grid system we use to pinpoint locations

Everything north of the equator is NORTH and everything south is SOUTH The Prime Meridian and the International Date Line are the Dividers for east and west-Everything west of the Prime Meridian is WEST and everything east is EAST until you get to the dateline.

We use degrees of latitude and longitude, which are an angular measurement from the center of the earth, to get precise locations.

Locations are intersections of degrees of latitude and longitude. Degrees are BIG, 69 miles apart, so we get more precise by using

Degrees, minutes, and seconds

One degree = 69 miles we are at 34° N and 117° W

But that is not very precise.

34° 28' N and 117° 15' W is more precise but minutes are still 1.15 miles apart or 6,072 feet

To get really precise we can use seconds, which are .02 miles apart or 100 feet and decimals to get as precise as within about 10 feet of a location.

For example this is the north end of the Liberal Arts building:

34° 28' 27" N, 117° 15' 48" W

Navigating the Campus with GPS

If you start from this location, 34° 28' 27" N, 117° 15' 48" W, and you are trying to find another location on campus, compare the locations.

If your seconds of longitude are larger than 27, then the location you are looking for is north. If your seconds of longitude are smaller than 27, then the location you are looking for is south.

If your seconds of longitude are larger than 48, then the location you are looking for is west. If your seconds of longitude are smaller than 48, then the location you are looking for is east.

Apps have a compass feature, you can use that to get your bearings. Name: ______

Please download one of the free apps.

Go into settings and make sure that you are set to degrees, minutes, and seconds, and make sure that your measurements are set to English.

Can you find the following locations? What is at each of these?

34°28'28.64"N, 117°15'43.13"W ______

34°28'25.46"N, 117°15'40.31"W ______

34°28'22.84"N, 117°15'45.18"W ______

34°28'24.29"N, 117°15'44.75"W ______

34°28'20.57"N, 117°15'45.69"W ______

34°28'20.70"N, 117°15'49.05"W ______

34°28'24.10"N, 117°15'48.47"W ______

34°28'23.92"N, 117°15'51.08"W ______

34°28'24.91"N, 117°15'53.85"W ______

34°28'29.19"N, 117°15'49.68"W ______