Grayce Mei FRS 142 2/26/07

GPS and Maps

The above picture is the waypoint of the Bike Rack from the Waypoint Hunt. It seems to

be in the general vicinity of the bike rack; it may be about a couple of feet off. This may

be due to various errors in the GPS, such as visibility, weather conditions, and

tropospheric and ionospheric delays.

Grayce Mei FRS 142 2/26/07

By Track

By elevation

Grayce Mei FRS 142 2/26/07

GPS and Maps

On February 23, 2007, Jonathan and I took a hike from Frist Campus Center to

the towpath and back around to Prospect Avenue back to Frist, walking for about 4.36

kilometers. The above pictures are of the track we took, with the first one colored by

track and the second one indicating altitude. These maps were obtained from

www.gpsvisualizer .com, with the text document derived from GPS Babel. I was able to

calculate my total distance, average speed, and total climb, and these results are displayed

below (taken from attached spreadsheet):

From Data Total Distance- meters 4621.477236 Total Time- seconds 2773 Avg. Speed- m/s 1.666598354 Total Climb- meters 43

I was able to calculate total distance by calculating the North-South Distance

((latitude1-latitude2) (pi/180) (6371000)), the West-East Distance ((longitude1-

longitude2) (pi/180) (6371000) (cos latitude1)), and using Pythagorean’s Theorem to

determine the straight line distance. Summing up all of these distances (except in the last

row, as it did not have a second longitude/latitude below it to subtract from), I ended up

with a track of 4621.48 m. These formulas can be found in my spreadsheet. Average

speed was calculated by dividing total distance by total time, coming out to be about 1.67

m/s. Total climb was determined by going through the spreadsheet and finding the

highest and lowest levels of elevation. Subtracting 13 m from 56 m, total climb was

calculated to be 43 m.

This lab has many potential places for error, as there seem to be many breaks in

the track, due to the faulty reception of the GPS, visibility, weather conditions,

Grayce Mei FRS 142 2/26/07

tropospheric and ionospheric delays, or interference from other devices/buildings. In

some instances, the displayed track was completely off, appearing as though we cut

across fields, fell off the bridge and swam in

the lake, and went through buildings. These

can be viewed below:

Grayce Mei FRS 142 2/26/07

From Data From GPS Total Distance- meters 4621.477236 4360 Total Time- seconds 2773 2810 Avg. Speed- m/s 1.666598354 0.372 Total Climb- meters 43 43

Above is the data gathered from the GPS versus the data gathered from the track

log data. The discrepancy in distance and time are due to the breaks in the track longs, as

the signal kept getting lost. This in turn affects the average speeds, which causes the

differences in those speeds.

My partner Jonathan Nussbaum’s data and track map is displayed below:

Total Distance (Meters): 4360.9692 Total Time: 46:40:00 Average Speed (m/s): 1.5574892

The difference in our distances is probably due to the fact that his GPS did not lose

reception as many times as I did (as clearly seen by comparing his track map to mine), so

therefore his data/track log is more accurate than mine. Our speeds were a little bit

different, but that is again due to the fuzzy reception on my GPS.