Using the Map Cursor

Working from the Map Page is a simple process that centers around the use of the cursor. Controlled by the ARROW KEYPAD, the cursor is an important tool that can be used to pan to other map locations, mark and edit waypoints and routes, and review position data of on-screen map items and waypoints. To get a feel for using the Map Page and using the cursor, try the following exercise:
1. Use the IN/OUT keys to set the map scale to the 50 nm setting. Your boat should be near the center of the map, at the receivers last known position. (If your boat isnt where it should be, make sure that you have initialized the receiver and acquired a position as described on pages 4-5.) 2. Use the ARROW KEYPAD to move the cursor. Notice how another data field appears, showing the bearing and distance from your boat to the cursor, along with the latitude/longitude of the cursor. 3. Press the QUIT key to remove the cursor and re-center your boat on the map display.
Getting Started Map Cursor
As you become more familiar with the cursor, youll see that the map display actively scrolls or pans, letting you explore areas around the world and create waypoints and routes. Wherever you move the cursor, pressing the QUIT key centers the map on your current position. Now that youve seen how the Map Page can be used to monitor your present location, lets take a minute to learn how to mark and store your present position as a waypoint. Since youre in simulator mode, the present position displayed is the last position calculated by the receiver, which should be the spot where youve initialized the unit. This also gives you an opportunity to see how the GPSMAP 178/178C Sounders keypad and ENTER/MARK key are used for data entry and changing the waypoint name and symbol.

Current position

Map Scale
Distance/ Bearing Cursor Coordinates Map Cursor
Getting Started Marking Waypoints
To mark your present position:
1. Hold down the ENTER/MARK key until the New Waypoint window appears then release the key. The window shows a default three-digit waypoint name/number (001), symbol (dot), and position. You can leave the name as the auto-assigned number, but for this exercise, lets change the name to DOCK. 2. Use the ARROW KEYPAD to highlight the waypoint name field (001) and press ENTER/MARK. You see that just the first 0 is now highlighted. 3. Press LEFT on the ARROW KEYPAD to clear the name field. 4. Press UP or DOWN on of the ARROW KEYPAD until the letter D appears, and then press RIGHT to go to the next space to the right, then UP or DOWN again until O appears. Repeat this until you have entered the name DOCK. If you make a mistake and select an incorrect character, simply press LEFT on the ARROW KEYPAD to backspace the cursor and then UP or DOWN to correct the entry. (If you accidentally press ENTER/MARK before you are done, simply press ENTER/MARK again and move the highlight to where you left off.) 5. After you have entered all the letters, press ENTER/MARK to confirm the name. 6. To access the waypoint symbol page, highlight the waypoint symbol field, which is to the left of the waypoints name and press ENTER/MARK. The default symbol is a dot. 7. You see a grid of available waypoint symbols to choose from. Use the ARROW KEYPAD to highlight the ANCHOR symbol. 8. Press ENTER/MARK to confirm the ANCHOR symbol. 9. Highlight OK at the bottom of the window and press ENTER/MARK again to confirm the OK prompt and save the waypoint.

Compass Ring Pointer Arrow
The current speed, distance to the next waypoint, turn angle, and time to the next waypoint display at the top of the screen. When you are not navigating to a waypoint, the compass shows your direction of travel as you move, but the arrow does not appear. The Compass Page allows for precision navigation to one degree of steerage. The default page displays one row of medium numbers fields. You may customize the Compass Page to display the size and number of fields along with the type data you wish to see. (See pages 30-31 for changing the types of data.) Press the PAGE key to display the Highway Page.
The GPSMAP 178/178C Sounders Highway Page also provides graphic steering guidance to a destination waypoint, placing greater emphasis on the straight-line desired course and the distance and direction you are off course. As you head toward your destination, the middle of the screen provides visual guidance to your waypoint on a moving graphic highway. Your present position is at the bottom center of the highway display. The line down the middle of the highway represents your desired course. As you navigate toward a waypoint, the highway actually moves, indicating the direction youre off course. To stay on course, simply steer toward the center of the highway or keep it on the road. The default data fields at the top of the page indicate Speed and Distance To Next point, along with To Course which shows the bearing to get you back on course and Time To Next point. Use the Highway Page as your primary navigation page (in lieu of the Compass Page) when your main concern is following a defined course. Whenever the GPSMAP 178/178C Sounder is in simulator mode, you can also adjust your speed and course from the Highway Page using the ARROW KEYPAD. As you head toward each waypoint in the tour route, try adjusting your boat speed and course to get a feel for how the Highway Page works. To adjust the simulated boat speed/heading from the Highway Page:
1. Press the UP arrow of the ARROW KEYPAD to increase the speed in 10 knot/kph/mph increments. Press the DOWN arrow to decrease the speed in the same increments. Press the LEFT and RIGHT arrows of the ARROW KEYPAD to steer the boat (adjust the heading).

Whenever you zoom in cursor mode, the cursor is centered on screen.
To return to position mode, press the QUIT key.
Reference Map Page: Cursor
When the cursor reaches the edge of the map, the unit may pause as it loads new map data.

Using the Cursor

The cursor allows you to pan away from your present position and scroll to other map areas around the world (even outside of your current detail coverage). As you pan past the edge of the current map display, the screen actively scrolls forward to provide continuous map coverage. You see an hourglass symbol by the pointer while the unit is busy drawing new map detail. To move the cursor:
1. Press the ARROW KEYPAD to move the cursor in an up, down, left or right direction.
As you move the cursor, the distance and bearing from your present position to the cursor is displayed in the data window, along with the cursors position coordinates. Keep in mind that when the cursor is stationary, the distance and bearing from your present position changes as your boat moves. The cursor may also be used to snap to on-screen waypoints and map items, allowing you to review a selected position directly from the map display. To select an on-screen waypoint or map item with the cursor:
1. Use the ARROW KEYPAD to move the cursor to the desired waypoint or map item (if there are several waypoints grouped closely together, zoom in closer for a better view). 2. When a waypoint or map item is selected, it becomes highlighted on screen, with the name and position displayed. Press ENTER to show details of the map item. When using BlueChart or MapSource data, additional information tabs appears. Use the ARROW KEYPAD to highlight the individual tabs to display the information and additional options.
Move the cursor over an item on the map to highlight it.
Additional information tabs. Pressing ENTER/MARK while highlighting a map item brings up additional details and options. Option buttons
Reference Map Page: Cursor and Zooming
To eliminate the cursor and re-center your position on-screen:

1. Press the QUIT key.

The cursor may also be used to create new waypoints directly from the map. To create a waypoint with the cursor:
1. Use the ARROW KEYPAD to move the cursor to the desired map position. 2. Press the ENTER/MARK key and the New Map Waypoint window appears. If the cursor is on a map item, you get a new window with details about the item when ENTER/MARK is pressed. Press ENTER again on the highlighted Create Wpt option. 3. Press ENTER to confirm the new waypoint using the default three-digit name and symbol.

Selecting Map Scales

Creating New Map Waypoint
The map display has 28 available range scales from 20 ft. to 800 mi. (5 m to 1200 km). The map scale is controlled by the IN and OUT keys, with the current scale displayed at the bottom right of the data window. To select a map scale:
1. Press the OUT key to zoom out and the IN key to zoom in.

Using Built-In Basemap

The scale value represents the distance from one end of the scale bar to the other.
Using BlueChart/MapSource Data
Overzoom, no additional data
The GPSMAP 178/178Cs system has a built-in worldwide database to 20 mi, with more detailed coverage available through the use of the optional BlueChart or MapSource data. The GPSMAP 178/178C displays cartography as long as there is chart information available for the range youve selected. Map coverage conforms to the following conditions: When the selected zoom range is covered by either the internal database, BlueChart, or MapSource data, cartography is displayed. When the selected zoom range is covered by both the internal database and BlueChart/ MapSource data, cartography is displayed using the data with the best resolution. When the selected zoom range exceeds the resolution of the data in use, overzoom cartography is displayed and an overzoom warning appears below the scale field.

Map Page Options

Many features of the GPSMAP 178/178C are menu driven. Each of the main pages have an options menu, allowing you to custom tailor the corresponding page to your preferences and/or select special features that specifically relate to that page. The data window, located at the top of the main pages provides a user-selectable layout of various types of useful data. Each data field may be configured to display any one of several data options. The data window layout may also be changed to display additional data fields and change the actual size of the data displayed. The GPSMAP 178/178Cs Map Page provides access to functions and features relating to the Map Page and the layout options. To display the Map Page options:

1. Press MENU.

Reference Map Page: Options

To select a menu option:

1. Use the ARROW KEYPAD to highlight the desired option and press ENTER.
The available options are Full Screen Map/Show Data, Measure Distance, Set Up Map, Set Up Page Layout, Change Numbers, and Turn Declutter On/Off. Following are details on using each of these options. Full Screen Map/Show Data toggles between a Map Page without or with data fields on the map display. The unit defaults back to Show Data the next time it is powered on. To maximize the map/show data fields:

1. Press and hold the ENTER/MARK key until the New Waypoint window appears, then release it. You see a default three-digit name and symbol for the new waypoint. 2. To accept the waypoint with the default name and symbol, press ENTER to confirm the highlighted OK prompt. 3. To enter a different name, highlight the name field and press ENTER, then use the ARROW KEYPAD to enter the new letters/numbers and press ENTER when done. You may use up to 10 alphanumeric characters for the name.
Highlight a field and press ENTER to enter a new symbol, name, comment, or depth.
4. To enter a different symbol, highlight the symbol field to the left of the name and press ENTER, then use the ARROW KEYPAD to highlight the new symbol and press ENTER. 5. To enter optional comments, depth, or water temp, highlight the appropriate field and press ENTER, then use the ARROW KEYPAD to enter a value and press ENTER.
6. To manually enter a set of coordinates, highlight the coordinates and press ENTER, then use the ARROW KEYPAD to enter the new coordinates and press ENTER when done. 7. When done, use the ARROW KEYPAD to highlight OK and press ENTER to save the waypoint into memory.
Creating Waypoints Graphically Waypoints may also be quickly created with the Map Page cursor, which allows you to point and shoot at any map position or map feature to create a new waypoint. When you move the cursor over a map item, you see a highlighted description of that item. The GPSMAP 178/178C uses the map item text shown on the cartography as the default name and symbol for the new waypoint. To create a new waypoint on an open map location:
1. Use the ARROW KEYPAD to move the cursor to the desired map position. 2. Press and quickly release the ENTER/MARK key to capture the cursor position (press and hold ENTER/MARK to mark your present location, not the map cursors position). 3. The New Map Waypoint Page appears. To accept the waypoint with the default name and symbol, press ENTER. To change the name, symbol, position, or add a comment, depth, or water temp, highlight the appropriate field and press ENTER. Make your changes and press ENTER when done. After entering and confirming your changes, highlight OK and press ENTER.
Creating a waypoint on an open map location.
To create a new waypoint from a map feature:
1. Use the ARROW KEYPAD to move the cursor and highlight the desired map feature. 2. Press ENTER/MARK to capture the cursor position. An Information page for that map feature appears. Use the ARROW KEYPAD to highlight Create Wpt and press ENTER. 3. The New Waypoint Page appears. To accept the waypoint with the default name and symbol (based on the map feature), highlight OK and press ENTER. To change the name, symbol, position, or enter comments, depth, or water temp, highlight the appropriate field and press ENTER. Make your changes and press ENTER. After entering and confirming your changes, use the ARROW KEYPAD to highlight OK and press ENTER.

Waypoint Menu Options

Two additional options are available by pressing MENU on the New Waypoint and New Map Waypoint Pages: Append To Route and Move Waypoint. (these menu options also appear on the Waypoint Edit and Waypoint Review Pages). Append to Route Adds the new waypoint to the end of a route. Move Waypoint Allows you to move the waypoint to a new location on the map display. To append a new waypoint to a route:
1. Select Append To Route from the options menu. 2. The Select Route screen appears. Highlight the desired route or select New Route and press ENTER. 3. With OK highlighted, press ENTER to save the waypoint.

Waypoint Options Menu

To move a waypoint:
1. Select Move Waypoint from the options menu. 2. The selected waypoint is centered and highlighted on a map display. Use the ARROW KEYPAD to move the waypoint to the new position and press ENTER. Press QUIT to exit.
Use the ARROW KEYPAD to move the waypoint to a new position on the map.
Reference Reviewing/Editing Waypoints
Reviewing and Editing Waypoints
Once you have created and stored a waypoint, it may be modified, reviewed, renamed, moved, or deleted at any time through the Waypoint Review and Waypoint Edit Pages. To access the Waypoint Review Page:
1. Use the ARROW KEYPAD to highlight the desired waypoint on the Map Page. 2. Press ENTER to display the Waypoint Review Page. If the waypoint is located on a map feature, or on a MapSource or BlueChart feature, the Waypoint Review Page includes additional information tabs about the other features at that location.
To access the Waypoint Edit Page:
1. Press MENU twice to view the Main Menu. Use the ARROW KEYPAD to highlight the Points tab, then highlight the desired waypoint from the User or Proximity lists.
Waypoint Review Page Highlight OK and press ENTER to exit/save changes.
2. Press ENTER to display the Waypoint Edit Page. If the waypoint is located on a map feature, or on a MapSource or BlueChart feature, the Waypoint Edit Page does NOT display the details of the other map features.
From the Waypoint Review and Edit Pages, you may change the name, symbol, comment, position coordinates, depth, or water temp for the selected waypoint. Once the changes have been made, highlight OK (Waypoint Review Page) or Next (Waypoint Edit Page) and press ENTER to save them. To change the waypoint name:
1. Highlight the waypoint name field and press ENTER. 2. Use the ARROW KEYPAD to enter a new name and press ENTER when done.
To change the waypoint symbol:
Changing a Waypoint symbol.
1. Highlight the waypoint symbol field to the left of the waypoint name and press ENTER. 2. Use the ARROW KEYPAD to select the desired symbol and press ENTER when done.

1. Press MENU twice to display the Main Menu. 2. Using the ARROW KEYPAD, highlight the Track tab, then highlight the Active tab to the right. 3. Use the ARROW KEYPAD to highlight Erase and press ENTER. 4. Highlight OK and press ENTER.
Highlight Save and press ENTER to save an active track log.
You must first save the track log before you can use the Follow Track feature. The Save feature allows you to store up to 15 track logs from certain times and dates. To save a track log:
1. From the Main Menu, use the ARROW KEYPAD to highlight the Track tab, then highlight the Active tab to the right.
2. Use the ARROW KEYPAD to select Save and press ENTER. 3. On the Save Back Through window, highlight the desired time, date, or Entire Log and press ENTER. 4. Next, the track begins saving and then display the Saved Track window when done. The default name, distance, and number of points (700 maximum) are displayed. To change the name of the saved track, highlight the name field and press ENTER, make your changes and press ENTER again. To choose a color that is used to display the saved track line, highlight the field and press ENTER, choose a Color and press ENTER again. To display the track on the Map and Highway pages, highlight the check box to the left of Show on Map and Highway and press ENTER. To view the track on the map, highlight Review on Map and press ENTER. Press QUIT to exit the Track Map window.
Reference TracBack Navigation
Default Track name Total Distance Change color of track line Check this box to display track Total number of points
5. Highlight OK and press ENTER to save the track.
To activate a TracBack using the NAV key:
1. Press the NAV key, then highlight the Follow Track option and press ENTER. 2. Highlight the track you wish to follow and press ENTER. 3. Choose either Original, which navigates you from the start to the end of your trip, or Reverse, which navigates you from the end to the start of your trip and press ENTER.
Once a TracBack has been activated, the GPSMAP 178/178C takes the track log currently stored in memory and divides it into segments called legs. Up to 50 temporary turns (BEGIN, TURN 1, TURN 2, TURN 3,., TURN X, END) are created to mark the most significant features of the track log in order to duplicate your exact path as closely as possible. To get the most out of the TracBack feature, remember the following tips: Always clear the track log at the point that you want to go back to (dock, etc.). The Record Mode option on the track log setup page must be set to Fill or Wrap. There must be at least two track log points stored in memory to create a TracBack route.
You must first save a track before using the Follow Track option. If there are no saved tracks, the message There are no saved Tracks to follow appears after you select Follow Track.
Reference TracBack Navigation/ MOB: Man OverBoard
If the track log interval is set to the Time option, the route may not follow your exact path (keep the interval set to resolution for best performance). If the receiver is turned off or satellite coverage is lost during your trip, the TracBack draws a straight line between any point where coverage was lost and where it resumed. If your track logs changes in distance and direction are too complex, 50 waypoints may not mark your path accurately. The receiver then assigns the 50 waypoints to the most significant points of your track, and simplifies segments with fewer changes in direction. To stop TracBack navigation:

WAAS Capability

The GPSMAP 178/178C is capable of receiving WAAS (Wide Area Augmentation System) satellite signals. WAAS is an FAA (Federal Aviation Administration) funded project to improve the overall accuracy and integrity of the GPS signal for aviation use, but land/sea based users may also benefit from this system. At this time, the system is still in the development stage and is not fully operational. There are currently two WAAS satellites that can be received in the U.S.A., one over the Atlantic Ocean and one over the Pacific Ocean, in a geo-stationary orbit over the equator. Effective use of the WAAS satellite signal may be limited by your geographic location in relation to those satellites, now in developmental service. WAAS satellite signal reception requires an absolute clear view of the sky and works best when there are no nearby obstructions such as buildings, mountains, etc. WAAS satellites are numbered 33 or higher when viewing the sky view on your GPSMAP 178/178C. Initial reception of the WAAS signal may take up to 15-20 minutes, then 1-2 minutes afterwards. When WAAS differential correction has been received for GPS satellites (numbers 32 or below), a D appears in the signal bar of the sky view and 2D or 3D Differential appears in the receiver status. To learn more about the WAAS system, its satellite positions and current state of development, visit the FAA web site (http://gps.faa.gov). Since WAAS requires CPU resources of the GPSMAP 178/178C to search for and track the satellites, you may disable the WAAS feature to improve unit performance if WAAS reception is not available in your area. To disable/enable WAAS capability:
1. From the GPS tab, press MENU, then use the ARROW KEYPAD to highlight WAAS Off or WAAS On and press ENTER.
Highlight WAAS Off and press ENTER to disable the WAAS capabilities.
Receiver Status and Accuracy
Receiver status is indicated at the top field of the page, with the current Accuracy and Dilution Of Precision (DOP) to the right of the sky view. Accuracy uses DOP and other factors to calculate horizontal position accuracy in feet or meters.
When the GPSMAP 178/178C is using a differential correction signal (either WAAS or DGPS), a D is displayed at the bottom of the signal strength indicator bars for the satellites that are corrected.
The status field shows one of the following conditions: Looking For Satellites the receiver is looking for any satellites. AutoLocate the receiver is looking for any satellite whose almanac has been collected. This process can take up to five minutes. Acquiring Satellites the receiver is looking for and collecting data from satellites visible at its last known or initialized position, but has not collected enough data to calculate a fix. 2D at least three satellites with good geometry have been acquired and a 2 dimensional position fix (latitude and longitude) is being calculated. 2D Differential appears when you are receiving DGPS corrections in 2D mode and a D shows on the strength bar of satellites being corrected. 3D at least four satellites with good geometry have been acquired and your position is now being calculated in latitude, longitude and elevation. 3D Differential appears when you are receiving DGPS corrections in 3D mode and a D shows on the strength bar of satellites being corrected. Poor GPS Coverage the receiver is no longer tracking enough satellites for a 2D or 3D fix. Receiver Not Usable the receiver is unusable, possibly due to interference or abnormal satellite conditions. Turn the unit off and back on to reset. Simulating the receiver is in simulator mode. The Differential Receiver status shows one of the following: Off No optional beacon receiver attached or enabled in the Comm menu or WAAS Off. Searching For WAAS WAAS is enabled and receiver is searching for WAAS signal. Using WAAS WAAS capability enabled and unit receiving WAAS corrections. No Beacon Signal DGPS receiver attached, but not transmitting RTCM data to GPS. Tuning Beacon Receiver is tuning manual DGPS frequency. Receiving Beacon Unit is receiving DGPS corrections. Scanning Beacon DGPS receiver is scanning for available frequency. Using DGPS Indicates a Differential signal is being received (only displays when the Serial Data Format is set to Other DGPS on the Comm Tab of the Main Menu).

The Units tab settings affect how navigation information is displayed on the GPSMAP 178/178C. When in doubt, seek assistance. If you are using a map or chart in conjunction with your GPS, make sure the settings under the Units tab of the GPSMAP 178/178C match that of the map or chart. This information should be displayed somewhere on the map or chart. If the information is not present, contact the map or chart maker to determine what position format, datum, heading and units of measure are being used for the map or chart.
Heading lets you select the reference used in calculating heading information. You can select from Auto Mag Var, True, Grid, and User Mag Var. Auto Mag Var provides magnetic north heading references which are automatically determined from your current position. True provides headings based upon a true north reference. Grid provides headings based on a grid north reference (and is used in conjunction with the grid position formats described on page 84). User Mag Var allows you to specify the magnetic variation at your current position and provides magnetic north heading references based upon the variation you enter. To enter a user defined magnetic variation:
1. With the Heading field set to User Mag Var, highlight the heading reference field (immediately to the right) and press ENTER. 2. Use the ARROW KEYPAD to enter the magnetic variation at your current position and press ENTER.
Distance, Speed, and Elevation lets you select the desired units of measure for distance, speed and elevation readouts in Nautical (nm, kt, ft), Nautical (nm, kt, m), Statute (mi, mh, ft), or Metric (km, kh, m) terms. Depth lets you select the desired units of measure for depth in Feet (ft), Fathoms (fa), or Meters (m). Temperature lets you select the desired units of measure for temperature in Fahrenheit (F) or Celsius (C).
WARNING: If User Mag Var is selected, you must periodically update the magnetic variation as your position changes. Using this setting, the unit does not automatically calculate and update the magnetic variation at your present position. Failure to update this setting may result in substantial differences between the information displayed on your unit and external references, such as a magnetic compass.
Reference Main Menu: Time/ Comm Tab
Time Submenu Tab displays the current time and date, allows you to adjust the 12 or 24-hour time format, enter a time zone, and adjust for daylight savings to show correct local time. The following options are available: Time Format 12 hour, 24-hour (military) or UTC time (also called Greenwich Time). Time Zone choose your time zone to show correct local time or choose Other and enter a UTC Offset. The UTC offset is how many hours you are ahead or behind the time line. See the table on page 96 for time offsets. Daylight Savings choose from Auto, On, or Off to adjust for daylight savings. Comm (Communications) Tab lets you control the input/output format used when connecting your GPSMAP 178/178C to external NMEA devices, a DGPS beacon receiver, a personal computer, another Garmin GPSMAP 178/178C, etc. If a DGPS receiver is used, WAAS capability is automatically turned to Off. The unit supports two input/output ports. See page 96 for more information on wiring and NMEA information. Individual Port settings are:

1. With the unit set to Garmin DGPS or RTCM In/NMEA Out, use the ARROW KEYPAD to highlight the Beacon field and press ENTER. 2. Highlight Scan and press ENTER. The numbers in the Frequency field changes as the unit scans from 284 kHz to 325 kHz, 200 bit rate, then 100, at 6-second intervals.
SNR and Distance shows data when signal is received.

To restart the scan:

1. Press MENU, highlight Restart Scan and press ENTER. The Status field shows one of the
following: Tuning unit is attempting to tune to the specified frequency and bit rate. Scanning unit is automatically scanning through the frequencies and bit rates. Receiving unit is receiving DGPS signal and ready for operation. Check Wiring unit is not making connection with DGPS receiver.
When the unit is receiving a DGPS signal, the SNR (Signal to Noise Ratio) and Distance fields shows data. The SNR range is 0dB to 30dB, with 30 being the best. The Distance may or may not show data, depending upon the signal being broadcast from the DGPS site.
You may also manually enter a frequency and bit rate.
The DGPS beacon transmitters are operated by the U.S. Coast Guard (or similar government agency in other countries), which is responsible for their accuracy and maintenance. For DGPS transmitter problems or to find the most updated list of frequencies and coverage areas, contact your local USCG, or see their web site at http://www.navcen.uscg.mil/

NMEA Interface

If you are going to interface the GPSMAP 178/178C with another piece of equipment (such as a radio or autopilot), the unit needs to be set to output NMEA data. More information on wiring and NMEA data may be found on page 96. To activate the NMEA data:
1. On either port of the Comm Tab, highlight the Serial Data Format field and press ENTER. 2. Select NMEA In/NMEA Out and press ENTER.
Advanced NMEA Output Setup
The GPSMAP 178/178C NMEA data transmission can be customized to change the precision of the Lat/Lon minutes, set up the waypoint IDs, and keep the output rate at two seconds. If the unit is set up to output all of the available NMEA sentences, the output rate may exceed two seconds. The Advanced NMEA Output Setup Page allows you to turn on/off the GPS status (GSA. GSV), Waypoint/Route (WPL, RTE), and the Garmin Proprietary sentences. See page 96 for more information on wiring and NMEA data. Lat/Lon Minutes Precision allows you to adjust the number of digits to the right of the decimal point for transmission of NMEA Output, either 2, 3, or 4 digits. The Waypoint ID setting lets you choose to output the waypoint identifiers as names or numbers. To set up the Advanced NMEA page:

PVC Pipe or a Can

Weight transducer to hold it in place
NOTE: Many modern hulls have a prelocated pocket for shoot-thru-hull transducer installation. If you are unsure if your hull is equipped with a pre-located pocket, contact your hull manufacturer.
Strip Caulk or RTV Sealer Hull Surface
Fill Pipe or Can with water or a light mineral oil

Testing the location:

1. Place the transducer in the water, pointed directly at the bottom and set unit for optimum performance. Place the transducer in the test device as show on the side bar. If the sonar performance is significantly degraded, another location needs to be tested.

Testing the Location

Installing the transducer:
1. Lightly sand the surface of the hull and face of the transducer with 400 grit wet or dry sandpaper. 2. Build a dam using strip caulk about 1/4 tall. Pour about 1/8 of two part, slow cure epoxy in the dam. Place the transducer in the epoxy, turning the transducer to work out any air bubbles. 3. Weight the transducer in place and allow to cure for 24 hours.

Testing the Installation

Appendix A Testing the Installation
While it is possible to perform some checks with the boat trailered, the boat should be in the water to properly test the sonar portion of the installation. Press the POWER button and the GPSMAP 178/178C should power on. If the unit fails to power on, verify that the wiring adapter is seated properly in the back of the unit, the Red and Black wires are connected to the correct polarity, and that the fuse is installed and not blown. If the unit is connected to a power supply that exceeds 35 VDC, a Battery Voltage High warning is displayed and the unit turns off. Since water is necessary to carry the sounders sonar signal, the transducer must be in the water to work properly. It is not possible to get a depth/distance reading when out of the water. As the unit powers on, it should immediately start showing the bottom. Verify that the unit is not in the simulator mode. If the unit is in the simulator mode, make sure that the transducer is connected to the wiring harness. To test the transducer installation, gradually increase the boat speed while checking the unit operation. If the unit displays intermittently or fails to display, verify that the transducer is aligned parallel with the bottom and if necessary, adjust the transducer height until the unit operates correctly. It may be necessary to make several adjustments to ensure proper operation throughout the speed range.

Appendix E Navigation Terms
Avg Speed The average of all second-by-second speed readings since last reset. Bearing (BRG) The compass direction from your present position to a destination waypoint. Course The desired course between the active from and to waypoints. Distance (Dist) The great circle distance from present position to a destination waypoint. Distance to Destination The great circle distance from present position to a Go To destination, or the final waypoint in a route. Distance to Next The great circle distance from present position to a Go To destination, or the next waypoint in a route. Elevation Height above mean sea level (MSL). ETA Estimate Time of Arrival. The estimated time you will reach your destination waypoint, based on current speed and track. ETA at Destination The estimated time you will reach a Go To destination, or the final waypoint in a route. ETA at Next The estimated time you will reach a Go To destination, or the next waypoint in a route. Fuel The fuel required to travel from present position to the indicated route waypoint. Leg Dist The distance between two route waypoints. Leg Fuel The fuel required to travel from a route waypoint to the next waypoint (in sequence) in the route. Leg Time The time required to travel from a route waypoint to the next waypoint (in sequence) in the route. Max Speed The maximum second-by-second speed recorded since last reset. Moving Average Speed Average speed while the unit is moving. Moving Trip Timer Total time the unit has been moving.
Odometer A running tally of distance travelled, based upon the distance between second-by-second position readings. Off Course The distance you are off a desired course in either direction, left or right. Also referred to as cross-track error or course error. Speed The current velocity at which you are travelling, relative to a ground position. Also referred to as ground speed. Time To The estimated time required to reach a Go To destination, or the next waypoint in a route. Also referred to as estimated time en route. Time to Destination The estimated time required to reach a Go To destination, or the final waypoint in a route. Time to Next The estimated time required to reach a Go To destination, or the next waypoint in a route. To Course The recommended direction to steer in order to reduce course error or stay on course. Provides the most efficient heading to get back to the desired course and proceed along your route. Track The direction of movement relative to a ground position. Also referred to as ground track. Trip Odometer A running tally of distance travelled since last reset. Also see Odometer. Total Average Speed Average speed of unit for both moving and stopped speeds since last timer reset. Total Trip Timer Total time the unit has been in operation since last reset of the trip timers. Turn The angle difference between the bearing to your destination and your current track. L indicates you should turn left, R indicates you should turn right. The degrees indicate the angle you are off course. VMG Velocity Made Good. The speed you are closing in on a destination along a desired course. Also referred to as the vector velocity to your destination.

DESTINATION WAYPOINT

DES IR TRA ED CK

'FROM' WAYPOINT

OF F CO UR SE

Appendix F Time Offsets

The chart below gives an approximate UTC (Universal Time Coordinate) time offset for the various longitudinal zones. Check with local charts for more detailed information. If you are in daylight savings time, add one hour to the offset. Longitudinal Zone W180.0 to W172.5 W172.5 to W157.5 W157.5 to W142.5 W142.5 to W127.5 W127.5 to W112.5 W112.5 to W097.5 W097.5 to W082.5 W082.5 to W067.5 W067.5 to W052.5 W052.5 to W037.5 W037.5 to W022.5 W022.5 to W007.5 W007.5 to E007.Offset -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 Longitudinal Zone E007.5 to E022.5 E022.5 to E037.5 E037.5 to E052.5 E052.5 to E067.5 E067.5 to E082.5 E082.5 to E097.5 E097.5 to E112.5 E112.5 to E127.5 E127.5 to E142.5 E142.5 to E157.5 E157.5 to E172.5 E172.5 to E180.0 Offset +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12
A simple way to determine your local time offset is how many hours you are behind or ahead of UTC (also called Greenwich or zulu time). Example: EST (Eastern Standard Time) is 5 hours behind UTC, so your offset would be -5. Adding one hour for daylight savings would make EDT (Eastern Daylight Time) - 4. Subtract an hour for each time zone as you travel west. Offsets for Continental U.S. would be: EST -5 CST -6 MST -7 PST -8
EDT CDT MDT PDT -4 -5 -6 -7

Understanding Sonar

If you are unfamiliar with basic sonar, or need help determining what is displayed on the graph, this section may be for you. This section is intended to help the novice user gain some understanding of how the GPSMAP 178/178C operates and how it can help improve their fishing productivity. To understand what the unit is displaying, it is important to have a general knowledge of how the unit works and how it determines what to display. Briefly described, the unit operates by transmitting sound waves toward the bottom of a lake, stream, or seabed in a cone shaped pattern. When a transmitted soundwave strikes an underwater object such as the bottom, a piece of structure, or a fish, sound is reflected back to the transducer. The transducer collects the reflected sound waves and sends the data to the unit to be processed and displayed on the chart. The underwater data is displayed on the chart in the order that it is returned: first returnedfirst on the chart. The diagram in the sidebar demonstrates this showing an underwater scene as it would be displayed on the chart. Generally speaking, if the only thing between the transducer and the bottom is water, the first strong return comes from the bottom directly below the transducer. The first strong return sets the bottom level. Weaker secondary returns provide the detailed data. Stronger returns displays in darker colors, black being the strongest return. In Example 3 (page 113) you can see that the branches and the fish where the strongest secondary returns are indicated in black on the display. That is brief description of how your GPSMAP 178/178C operates. Lets take a look at how this data can help you to improve your fishing.