Spreadsheet Graphing Applications for using GPS
From OpenContent Curriculum
For those who wish to incorporate GPS technologies skills into the standards as they are, you can use the latitude / longitude coordinates as graphable data. It is important to choose data that will work. Degrees, minutes, and seconds would be very difficult to use. Other systems which break the data into decimals will work. The common degrees and decimals of minutes work as long as you only graph the decimal portion of the coordinate.
Data may be entered into a spreadsheet as follows:
Acquiring Basic Data Coordinates
For this example, a series of coordinates were gathered by having students walk around the perimeter of the school grounds. This resulted in seven pairs of coordinates we could use for data.
Graphing the Raw (y,x) Data
This data entry will produce a simple outline of the data entered though it will not be to scale nor oriented properly. It does accomplish the basic graphing of the data. Corrections are a more advanced skill and build on the basic data.
Correcting the Data Order
Some students may recognize the fact that x,y coordinates taken straight from lat/lons are in the reverse order necessary for proper graphing. Copying and pasting to get them correctly ordered for graphing will partially correct the graph.
East/West Quadrant Correction
Western (and Southern) hemisphere coordinates involve negative numbers rather than "west" or "south" to indicate their place on the Cartesian graph. When the "west" coordinates are corrected, the graph produced will look correct in very way except for its scale.
To determine the distance ratio of the lat / lon coordinates, you may choose to use the GPS to help you by comparing like units (degrees or minutes) in both latitude and longitude with equally different coordinates in both directions from a given waypoint in the GPS. (Three waypoints are needed in the GPS; they can be contrived [programmed artificially]).
Comparing their actual distance by placing them into the "route" menu on the GPS will show their actual distance on the ground.
Scaling the Map
Comparing the two distances will give you their ratio. (As a Social Sciences standard adaptation, you might also use two imaginary pairs of coordinates from nearer the equator to show how it changes because of Earth's shape.)
The final graphic image may be pulled to proper scale using the found ratio.
Some might say, "Gee, my GPS does all this for me and more. Why should we do this when the technology already exists to do so much more so easily?"
It should be noted that the basic skills used and taught here are much like learning math facts when there are calculators which can do the same things and much more. There is a lot of value in basic skills - and a lot more application one can make of excellent techologies when they have a good handle on the basics.
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