WILD 2400 ASSIGNMENT #1: GPS TUTORIAL*

Transcription

1 WILD 2400 ASSIGNMENT #1: GPS TUTORIAL* Overview: In this tutorial you will learn how to collect, download, and display data using a Garmin GPSMAP 64 unit, the DNRGPS Application, and Google Earth. For additional information on the Garmin GPSMAP 64, refer to the owner s manual at Note that while this tutorial was written for the Garmin GPSMAP 64, other Garmin units such as the etrex series are similar. Tutorial Objectives and Skills: Become familiar with basic functions of a GPS o Learn how to identify and change the projection in which data are displayed on the GPS o Manually enter a waypoint o Navigate to a point o Learn how to create a TrackLog with the GPS to record your walking path o Collect Waypoints Learn how to retrieve data from the GPS unit and display it in a GIS o Download collected tracks and waypoints from your GPS to your computer using the Minnesota Department of Natural Resources DNRGPS Application o Export and view your points and tracks in Google Earth Getting Started: The Garmin GPSMAP 64 is a consumer grade GPS receiver that is generally used for recreational GPS activities. Consumer grade GPS receivers typically have locational accuracy of 3 to 10 meters, assuming WAAS correction (Wide Area Augmentation System, and a clear view of the sky. While accuracy of these receivers may be limited when compared with mapping or survey grade GPS units, these units are affordable, easily portable, and relatively easy to learn operate. Researchers who understand the limitations of data captured using a consumer grade device can effectively utilize those data for many types of studies where high accuracy and precision are not required. The DNRGPS application that we will use in this tutorial is a freely available tool developed by the Minnesota Department of Natural Resources. The program was developed to facilitate the use of data collected by individuals involved in outdoor recreational activities and to support state programs. The DNRGPS application provides the ability to upload and download points, convert collected waypoints and tracks to shapefiles (for use in a GIS), and export all waypoint or track data to Google Earth KML (keyhole markup language) files. The DNRGPS application is available on Canvas and at *Modified from a GPS tutorial developed by Chris McGinty, USU WILD

2 2 Step 1: Set the coordinate system of the GPS Turn on the GPS unit by holding down the power button on the right hand side for a few seconds. The default Position Format (coordinate system) is WGS84. This should be changed to UTM UPS, and the Map Datum should be set to NAD83. The Universal Transverse Mercator (UTM) Universal Polar Stereographic (UPS) coordinate system uses a metric-based Cartesian grid system to locate positions on the surface of the earth. The UTM system is not a single map project. The system instead divides the Earth into 60 zones, each a six-degree bad of longitude. Utah is in zone 12T. A Map Datum describes the model that is used to match the location of features on the ground to coordinates and locations on the map. The North American Datum 1983 (NAD83) is a commonly used datum in North America. You should always set your GPS unit s datum to match the datum of the map you are using. To set the Position Format and Map Datum, press the Page button until Main Menu is centered and press Enter. Use the arrow rocker to highlight Setup and press Enter. Use the arrows to highlight Position Format (down the list) and press Enter. Select UTM UPS for Position Format, and NAD83 for Map Datum: Press the Quit button to exit out to previous menus. Step 2: Enter coordinates into the GPS The instructor will provide you with coordinates for a series of campus locations that you should enter into the GPS and navigate to. To enter the coordinates press the FIND button and use the arrow rocker to highlight Coordinates and press Enter. Use the arrow rocker and the arrows on the screen to move through the numbers and make changes to match the UTM coordinates for each location, and highlight Done when you are finished and press Enter. Separately enter UTM coordinates for each location.

3 3 Step 3: Navigate to each Point 1. Take your GPS outdoors. a. Note that if the GPS has not been outside for some time, it will need a few minutes to acquire a new GPS almanac and find the available satellites. While it is searching for satellites and downloading almanacs, a question mark will flash. b. To view the satellites which your receiver has found, navigate to Main Menu (using the Page button and pressing Enter when Main Menu is centered). Use the arrow rocker until Satellite is highlighted and press Enter. c. How many satellites can you see as being active? Which coordinate system is your GPS unit displaying? 2. Press the Page button until Map is centered, and press Enter to view the navigation map. a. The triangle shaped arrow represents your location and the thumbtack icon marks the coordinates you entered using the Find button, with the default label Coordinates. The pink line is a straight line connection between you and the target coordinates not recommended walking path. You can use the IN and OUT buttons to zoom in and out; also notice the scale bar. The rocker may be used to pan around the screen; this will also bring up the coordinates at the top of the screen. Only large or main roads will be displayed in the background.

4 4 b. Because the GPS calculates most values using velocity measurements, you need to begin moving to get the arrow to give you an accurate direction of your movement. Remember to also look up and pay attention to your surroundings and choose the safest route. Step 3: Record your path 1. Activate the Track Log feature before you start navigating to your points. The track log is a feature that, when turned on, takes a GPS reading every few seconds. This is stored as a track file which can be saved as points, a line, or a polygon using DNRGPS. As you navigate to each point, it will track the path that you walk. This is a useful feature for keeping track of your route in the field. Go to Main Menu Setup Tracks, press Enter on Track Log. Scroll down to Record, Show On Map and press Enter. If Track Log was previously turned on, go to Main Menu Track Manager Current Track, select Clear Current Track at the bottom and confirm Yes, that you want to clear the track. This will allow you to collect your trip as a new track.

5 5 You can leave the screen on the track log page, or use the Page button to go to the Map Page, which is useful for viewing the big picture, or press Page to the Compass page for navigation, or Page to the Trip Computer. Keep in mind when the last time these counters may have been restarted to evaluate what the times, speeds, and distances are describing. 2. After you finish navigating to each point but before re-entering the NR building, save your track log by going to Main Menu Track Log Current Track, and Save Track. You can change the track name (the default name is the date and time) to indicate that it was your trip, and to eliminate any confusing with previously stored tracks when you download. Choosing Yes to clear the current track will ensure that the next track you collect does not include this practice trip. 3. Stop the Track Log function by going to Main Menu Setup Tracks, and in the Track Log box choose Do Not Record. If you fail to stop the logging process, the GPS will continue to try to log points but they will have considerable error and your future track logs will look strange when loaded into the GIS, or they will clutter your map screen unnecessarily.

6 6 Step 4: Mark waypoints 1. Mark a waypoint at each point you navigate to. To mark a waypoint, press the MARK button. Your current location will be instantly recorded as a new waypoint. You have the option to rename the point or to enter a note. With the name field highlighted (usually 001 as the default), press Enter. This brings up a keyboard that you navigate around using the arrow buttons and the arrows on the screen. 2. Rename the point with the correct letter designation (A, B, C, D, E, or F). In the note field, indicate whether the surface beneath your feet at the location is GRASS or PAVEMENT 3. Choose Done below the keyboard when you are finished. You can do the same in the Note box to add information about your point. Then use the rocker arrows to highlight Done on the point description page and press Enter. The point name and any notes will be transferred as attributes in your final points Google Earth KML file. Step 5: Download your Waypoints and Track Log with DNRGPS Application 1. After you have navigated to all your points, recorded waypoints, noted surface conditions at each, and recorded your path, return to NR 217 to download the data to your laptop. If necessary, you and your partner(s) can work together on the same laptop. 2. Start the DNRGPS application. 3. Plug the small end of the USB cable into the USB mini port on the back of the GPS. Plug the large end of the USB cable into the USB port on the computer. In DNRGPS, click GPS Find GPS.

7 7 4. Set the coordinate system of DNRGPS a. Choose File Set Projection and from the Datums: drop-down menu, choose NAD83, and from the Projections: drop-down menu, choose UTM zone 12N b. Click OK to finish.

8 8 5. Download and export your waypoints: a. From the Waypoint drop down menu choose Download. b. All of your waypoints are stored in a single file with the date. Select the Waypoints_ file and click OK to download. c. You should get a message indicating that your download has completed, and a table will display with all of your waypoints, with names, notes, and X, Y values in latitude and longitude and in the projection you selected, altitude, and a date/time stamp. d. Highlight the waypoints you want to export. Choose File Save To File and from the Save as type: drop-down menu, choose Google Keyhole Markup Language (*.kml) 6. Download and export your tracks. a. From the Tracks drop down menu choose Download b. Select your Track_ file and click OK to download. c. You should get a message indicating that your download has completed, and a table will display with all of the points that comprise your track, with the same detailed information as the waypoints. Notice that the track is comprised of many points and the beginning segment is identified as new_seg with a value of True. d. Highlight all of the components of the track for export. Choose File Save To File and from the Save as type: drop-down menu, choose Google Keyhole Markup Language (*.kml) e. For this exercise, choose Shape Type: Line, but note that your track could also be exported as the other shape types.

9 9 Step 6: View your KML files in Google Earth & construct a map 1. Open Google Earth and use the File menu Open to add your KML files. 2. You can edit the symbology of your points and tracks in Google Earth. In the table of contents, right click on the layer to open the Properties > Style, Color Tab. You may need to click the Share Style button to apply the style to the descendant(s) of the folder. 3. Label each of your waypoints with the correct point letter designation (A, B, C, D, E, or F). Be sure to center the map so that all 6 locations are visible. Exclude all other extraneous information from the map by turning off any extra data layers listed under Layers. 4. Save your map as a JPEG file: Choose File Save File Save Image. Use your name as the file name, e.g., lab1_map_dan_macnulty 5. Upload your map using the upload function provided in Canvas Quizzes Assignment 1: Orienteering & GPS Question 32 Example Map: