Project 2: Locating Geographic Coordinates with GPS

Project 2: Locating Geographic Coordinates with GPS

Presented By: Kurt Ehrenfeuchter, Sally Ho, and Justin Hoy

GPS (Global Positioning System)

GPS is a system to calculate aposition or coordinate on the Earth’ssurface. GPS consists of a “space”component and a “user” component.The “space” component refers tonumerous satellite’s that are constantly orbiting the earth sendingcoded signals. The “user” componentrefers to receivers that decodesatellite signals and use them toprocess information (such a distancesfrom the satellite/s).


GPS uses the process of triangulationto approximate the location of where a “user” is receiving a signal on the Earth’s surface. As seen in class, the greater the distance between satellite’s, the moreapproximate the GPS reading will be.In conjunction with this, the moresatellite’s used, the more precise theGPS reading will be.


Although GPS systems are excellent examples of howTechnologically advanced we have all become, it does have its down falls that we must be aware of and consider while using GPS software.

The first problem with GPS is atmospheric delay. The coded signalbeing sent by the satellite must travel tremendous distances and“bounces” off things when coming through the ionosphere andtroposphere. This increases the time it takes to be received anddecreases the accuracy of the GPS reading.


The second problem involves a term known as multipath. Ideally, the

signal would come to the receiver in a straight line (thus taking the leastamount of time), however, due to reflections in the atmosphere and onthe ground the signal can be redirected before reaching the receiver.This interrupts the signal increasing the time it takes to reach the user,as well as decreases the accuracy of the GPS.

The third problem is obstruction. This is pretty self explanatory inthat sometimes features on the landscape interrupt the ability forsignals to be received by GPS instruments. Things such as forests,cities, and steep mountains are all example of obstruction.


Now that we have reviewed the basics of GPS we can getready to talk about Project 2!However, keep in mind the kindsof things that can interfere with theaccuracy of a GPS reading, you mayfind that you experience some ofthese inaccuracies when yourconducting your work!

Project 2: Locating Geographic Point with GPS

Project 2 is divided into two different parts:

The first part of the project is referred to as 2a. In this section youwill work in groups of 3 to 4 people (no flying solo on this one!), and

youwill locate two different locations on campus by using a GPS handheldreceiver. This will acquaint you with how to read the data on the GPSand get use to using its various settings.

So really, your going on a GPS scavenger hunt!!


Part 2a Continued…

Once you feel comfortable with the GPS and have located your twolocations on campus, you can move onto the second part of 2a. Nowyou get to learn how to record certain locations within the GPS device.These are called waypoints, by following a simple process that we willdiscuss in a few slides, you can record points into your GPS for lateruse. For this part of the project, you and your group must travel aroundcampus and record 4 different locations (make sure they are far enough apart so they can be visible on a map) as waypoints. Makesure every member records a location, and these locations can rangefrom historical landmarks around Penn State to the place you drankyour first beer, don’t be afraid to be creative!



Before you embark on part 2a of this project your going to needsome supplies. One member of your group is going to need to sign outa GPS handheld receiver from your TA (that’s Missy!). In addition tothis, you’ll need to acquire a copy of the handout prepared by Missy,telling you the latitude’s and longitude’s of your locations on campus tofind using your new GPS receivers.



Your GPS receiver is a GarminGPS 12 Personal Navigator, whichcomes in a carrying case and a copyof the owner’s manual for the unit. Iwould strongly recommend readingpages 5-11 of the owner’s manualbefore turning on the GPS unit to getfamiliar with how it works and to savebatteries. Although we will go throughsome of the basic features of theGPS receivers.


Using the GPS receivers:

The first step to using any electronic device is to turn it on! Thepower button for the unit is located on the left hand-side above thescreen between the “GOTO” and “QUIT” buttons (it has a red light bulbon it). Once the GPS receiver is powered up it will take you to the firstof 5 possible screens, the first being the Satellite Page. Your most

likelygoing to have to wait a few minutes for the receiver to communicatewith the satellite/s (our first experience with atmospheric delay) andshow you which one’s it can establish a connection with.



Once you are connected with the satellite/s push the “PAGE” buttonlocated on the upper right. This takes you to the Position Page. Thispage gives you valuable information such as your position (i.e. latitudeand longitude) as well as your elevation, heading, time, and evenspeed at which you are traveling. This is the screen you will primarilyuse for the first part of 2a (locating your two mystery points).



Now since we are a nice leadership team and don’t want you running around aimlessly looking for your points we are going to save you some confusion that we bumped into when we started searching. If you look at your Position Page on your GPS you’ll see that the lat. and long. are recorded in degrees, minutes, and seconds. This normally isn’t a problem except that on your worksheet your lat. and long. are in decimal degree format. An easy fix to this problem is to go to the website:

http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html

and type in your coordinates. (Your welcome!)



Now that you have coordinates inthe same format as your GPSreceiver you can begin to locate yourtwo mystery locations. Be sure tobring your owner’s manual and extrabatteries incase you run into anyproblems along the way. You will alsoneed your worksheet to documentwhere your coordinates take you!



As discussed earlier, this part of the project involves recording 4different locations around campus (be sure they are far enough apartthat they can be easily viewed on a map). These can be anywhere onthe campus map provided (i.e. between Walker and the HUB) and they canbe your houses, where you work, historical sites, or even where youdrank your first beer, etc. Each member of your group should recordone point in the GPS receiver.

Recording points in the GPS receiver is an easy process that we willillustrate now for you….



Once you get to the location that you wish to record onto your GPS, pushthe “MARK” button (the middle right button) and it will take you to a new screenthat says waypoint at the top. At this screen you should see the latitude andlongitude of the point you want to store, this means that the GPS hasrecognized your location, but before you move on make sure you save thepoint by highlighting the “save” option on the lower right and hitting “ENTER”.You need to get 4 waypoints and each member of your group should have aturn to record a point. (Before you actually begin this process it might be a goodidea to go into the waypoint screen and delete any previously markedwaypoints to save time later!)


Project 2b:

Now that you have found the two mystery points and have plotted your own4 locations, it’s time to move on to the last part of the project. Your group willhave to go to the Walker Building computer lab (room 208), and get a specialcord to connect your computer to the GPS. Once you are connected you willhave to download your data using the waypoint software, format it correctly inMicrosoft Excel, and then use Excel to import and plot your points onto a mapin Arc View. This portion of the project is fairly detailed, so if you would like tofollow along with the description of this section o the project you may do so bygoing to:

http://www.geog.psu.edu/courses/geog121/projects/proj2b.html


Project 2b continued….

Step 1 is to hook your GPS up to the computer via a special cable providedin Walker building. Once connected you must open up the waypoints programlocated under the Geog121 tab found in the START menu.

Step 2: Once the program is up and running you have to download yourwaypoint from the GPS onto the computer. To do this, just simply go to the“GPS” tab, select the “download from GPS” from the pull down menu, and fromthere select “waypoints.

Step 3: Once your waypoints are highlighted go to File and select“configuration”, in “configuration” change your settings to Decimal Degrees andStatute Miles (this is the default settings for the program, they must be in thissequence because the datum you will have to use is measured in feet and anyother setting will distort your map).


Project 2b continued….

Step 4: Next you have to select whatdatum you are going to want to use, to doso you must go to File and on the pulldown tab select “Datum”. This projectrequires that you use the “WGS84” datumlocated towards the bottom of the list,because this datum corresponds to themap you will need to plot your waypointson.

Step 5: Is to simply save yourprogress thus far, to do so go to File onthe pull down tab select “Save” and then“waypoint”.


Project 2b continued…

Step 6: You will now need to open your newly saved waypoint file into MicrosoftExcel. To do so, open Microsoft Excel, select File and “open”, make sure the file typemenu is set to either “text file” or “all files” otherwise you will not be able to view your file.When you do this you will be prompted by a pop-up screen to “delimit” your data, just

simply follow the onscreen instructions to NOT delimit your information.



Step 7: Once you have followed all of the “delimiting” instructions yourinformation will open in Excel. Your latitude and longitude for your variouspoints will be listed, along with extra information such as the date, time, etc.You only need the information listed under tabs C, D, and E (latitude, longitude,and waypoint number). After you delete all the other information except therequired fields, you can rename them as “waypoint”, “latitude”, and “longitude”.We will demonstrate this for you on the next slide.




Step 8: Once you have formatted your file, you must save it. Be sure yousave your file as a text file (.txt) because you can’t use Excel files in ArcView.

Step 9: Next you will have to go to angel and download the zipped PennState Campus map. This file is listed on angel as “Project 2b: Campus MapData” and follow the instructions given on angel for properly downloading thefile.

Step 10: Once you have downloaded and unzipped the Map file open ArcView and select a new map. To import the Penn State map form angel, youneed to select he button located to the left of the scale (it looks like a yellowstreet sign with a plus sign on it). You will need to load each layer (i.e. mask,roads, etc) individually. Make sure you load the mask layer first, followed by the others.




Step 11: After you have loaded all the layers and can view the map, you have to verify your coordinate system. To do so, right-click on the layers page (left side) and select “Data Frame Properties”, when this opens go to the “coordinates” tab and make sure your coordinate system is set to the “NAD_1983_State Plane_Pennsylvania_North…..”. You must use this coordinate system because it is currently the most up to date system in this program.



Step 12: The next step involves loading your GPS waypoints onto yournewly created map in Arc View. To do this, go to the “Tools” tab, select “Add XY Data” from the pull down menu, and a new screen will appear showingyou the settings for your data. At this point you should put in your table from excel. From here you need to tell ArcMap what Datum you are going to use, so where it says “Spatial Reference of Input Coordinates” find the edit button and it should take you to another menu. From this menu go to select, that will then take you to the folder with coordinates systems in it. There are a lot of different choices in here but the one we are looking for is WGS 1984. So you want to go to the “Geographic Coordinate Systems” then choose the “World” folder, and in the World folder you should see the WGS 1984.prj Datum. (last one in the list)



Step 13: Once you have verified your data, hit ok and upon doing so a new layer called “waypoints” will appear under your layers listing. This will display your waypoints on the map!

Step 14: The final step just involves saving your map as a screen capture so you can load it onto your webpage at a later date. To do this, just locate your “Prnt Scrn” button, it may be located in the upper right, or as a function key depending on what kind of computer you are using. While in the screen you want to save, simply press “Prnt Scrn”, then go to whatever you are going to save the image to and paste it.

Congratulations! Your almost there!


Project 2:

Now that you have successfully made your map consisting of your GPSpoints, you can go on to the final stage of the project. If you would like to seean example of how your finished project should look like, you may do so at thefollowing webpage:

http://www.geog.psu.edu/courses/geog121/projects/proj2b_example.html

The final copy of Project 2 requires your name, the image of the screen captureyou saved, followed by a description of the points you plotted, experiences, andthe equipment used. This will then need to be uploaded onto your personalwebpage and hyperlinked under “Project 2”.


References:

Baxter, Ryan. Lectures 6 & 7 – GPS. Class notes for Geog 121, Penn StateUniversity, 2006.

Degrees, Minutes, Seconds and Decimal Degrees Latitude/LongitudeConversions. http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html.Accessed 6 October 2006.

Geography 121 Project 2b (Example) .http://www.geog.psu.edu/courses/geog121/projects/proj2b_example.html. Accessed 6 October 2006.

Geography 121 Project 2b. http://www.geog.psu.edu/courses/ geog121/projects/proj2b.html. Accessed 6 October 2006.

http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html


Contact Page:

Kurt Ehrenfeuchter, [email protected], cell (717)-571-5168

Sally Ho, [email protected]

Jason Hoy, [email protected], cell (814)-883-6737http://www.personal.psu.edu/jeh5003

Documents

Project 2: Locating Geographic Coordinates with GPS