GPS

(This function is only available in OCAD Professional!)

Real Time GPS

Choose this command for mobile mapping with GPS. The GPS device must be connected to the PC with a data cable or Bluetooth.

It is important that the coordinate system on the GPS device is WGS84 or a UTM zone. Otherwise OCAD cannot analyze the data correctly and the position is wrong (some 100 meters)!

Real Time GPS Settings

Choose this command to open (activate) a GPS device connected to your computer.

Connection settings

• Port: Choose the COM port where the GPS device is connected. The GPS device must send the [NMEA 0183 format].
• Speed: Choose the speed of the serial port. NMEA 0183 defines 4800 bps but some devices may send data at a different speed.
• Test: Click Test button to open Test GPS dialog box. The NMEA messages received from the GPS device are displayed there.

Requirements

• DGPS, RTK, Float RTK: Check this option to use DGPS, RTK, Float RTK and define if the positions calculated without DGPS, RTK, Float RTK are not saved or not saved and not shown.

This option has only an effect if OCAD receives the [GGA message]. Click the Test button to see what type of message is sent from the device.

• Min. 4 satellites: Check this option as a kind of precision requiremen and define if the positions calculated from less than 4 satellites are not saved or not saved and not shown..

This option has only an effect if OCAD receives the [GGA message]. Click the Test button to see what type of message is sent from the device.

• HDOP: Check this option to define an upper limit for the HDOP value and define if the positions calculated with a higher HDOP are not saved or not saved and not shown..

Options

• Filter: Check this option to activate a filter and specify how many GPS positions are averaged. This results in a more stable position, but the update is slower.
• Accuracy circle: Check this option to show the accuracy circle. This shows the accuracy of the last 5 measurements with a circle around the GPS marker.
• Auto scroll (moving map): Check this option to move the map automatically with the GPS marker.
• Subtract antenna height from Z value: Check this option to define a correction for the Z value.
• GPS real time mode: Choose between Geo-referenced mode (since OCAD 9) and Adjusted mode (until OCAD 8).

Coordinate system: Click this button to change the coordinate system. The dialog box Coordinate system appears.

Turn On Real Time GPS Click the OK button to turn on real time GPS. The GPS box is displayed in the lower right.

Turn Off Real Time GPS Close the GPS box or click the Cancel button to turn off real time GPS.

Test GPS

Serial data: If OCAD receives [GGA messages], those messages are displayed here. Characters 4 to 6 show the abbreviation GGA (e.g. $XXGGA...). [RMC messages] are displayed if OCAD does not receive any GGA messages. RMC messages contain no information about DGPS and the number of satellites. However, the position can still be used in OCAD.
The serial data box remains empty, if the GPS device is sending neither of the two messages or if there is a connection problem. Check that you have selected the right port in the Real Time GPS Settings dialog box and that the GPS device is connected correctly to the PC.

GGA sample message:: $GPGGA,092750.000,5321.6802,N,00630.3372,W,1,8,1.03,61.7,M,55.2,M,,*76

RMC sample message:: $GPRMC,092750.000,A,5321.6802,N,00630.3372,W,0.02,31.66,280511,,,A*43

Mapping with Real Time GPS

The GPS box is displayed in the lower right if real time GPS is turned on.

• Easting: In this field the easting value of the coordinate is displayed. If the filter is activated then it is the averaged value.
• Northing: In this field the northing value of the coordinate is displayed. If the filter is activated then it is the averaged value.
• Height: In this field the height is displayed. If the filter is activated then it is the averaged value.
• DGPS: A green or red dot shows if DGPS signal is received.
• Satellites: In this field the number of received satellites is displayed.
• HDOP: The HDOP (horizontal dilution of precision) is displayed in this field. HDOP is a quality indicator for the position of the useable satellites on the local sky. HDOP values less than 4 are very good, HDOP greater than 8 are bad.
• Precision (x Val): In this field the accuracy (root mean square) of specified number of last measurements is displayed. Filter length can be specified in Real Time GPS Settings.

• Start GPS Measurement: Click this button to create an OCAD object with GPS. A symbol must be selected. Choose a point symbol to create an object to the GPS marker. If a line or area symbol is selected, OCAD starts with measurement and drawing. The object is represented with a thin black line.
• Pause GPS Measurement: First click: Interrupt GPS measurement without finishing the object.

Second click: Go on with GPS measurement.

• Stop GPS Measurement: Click this button to finish the line or area object. The object is displayed with the assigned symbol.
• Find: Click this button if the GPS marker is not in the drawing windows. The view moves to the GPS marker.
• Filter: Turn on/off filter. See also: Real Time GPS Settings.
• Accuracy circle: Turn on/off accuracy circle. See also: Real Time GPS Settings.
• Point mode:

Choose Normal point option when for every position received from GPS a point should be added to the object.

Choose Corner point option when a position should be manually added to the object by clicking Start GPS measurement button. This option is typically used to draw objects with straight parts and corners like a fence. Point mode cannot be changed if a point or text object is selected.

• Add position to calculate average: Click this button for every position you want include into an average calculation. The number of added positions is shown in the button hint. Click Start GPS measurement button to create the object at the calculated average position.
• Open Real Time GPS Settings: Open the Real Time GPS Settings dialog box.

The GPS cursor is drawn with the mark color. Select OCAD Preferences and Drawing and Editing in the Options menu to change the mark color.

Adjust Local GPS Position

This command is activated when Real Time GPS is turned on and Adjusted mode is set in the Real Time GPS Settings dialog box.

Choose this command to adjust your base map to the coordinates provided by the GPS. The Adjust GPS dialog box is displayed. You can use up to 32 points for the adjustment. The existing adjustment points are listed in the box Adjustment points.

Note: You can turn on/off each adjustment point by checking it or not.

• Close: Close the dialog box by clicking this button. Adjust GPS is a non-modal dialog.
• New: You can create a new adjustment point when you are at a known position in the terrain and your GPS device the position. Click this button and the cursor changes to a satellite symbol. Mark your position on the base map. The point is added to the adjustment points and the adjustment is recalculated.
• Rename: Click this button to rename the selected adjustment point.
• Delete: Click this button to delete the selected adjustment point.
• Angle: If you use only one adjustment point, you can enter the angle of your map here. You must enter the angle of your map compared to the WGS84 coordinate system used by GPS. The angle of the WGS84 coordinate system is normally different from your country’s coordinate system. If the map is rotated counterclockwise, enter a positive angle otherwise enter a negative angle.

If more than one adjustment point is used, the angle is calculated from the adjustment points. In this case the Angle value is not used.

Import Data from GPS Device

Choose this command to import tracks or waypoints from a GPS Garmin eTrex. The GPS device must be connected to the PC with a serial data cable or Bluetooth.

• GPS: In this field the information about the GPS device is displayed.
• Status: In this field the status between OCAD and GPS is displayed.

Connection

• Connect GPS: Click this button to connect OCAD with GPS device. After successful connection the GPS information and the status are displayed.
• Settings: Click this button to change the GPS settings. The dialog box Import from GPS Settings is displayed.

GPS data

• Get waypoints: Click this button to load all waypoints. Each waypoint is displayed with a line in GPS data field.
• Get tracks: Click this button to download all tracks. Each track is displayed with a line in GPS data field. Only the start point is displayed.

This command can take several minutes!

OCAD objects

• Set labels: Check this option to create also text objects with the name of waypoints and tracks.
• CRT: Click this button and choose a cross reference table (*.crt). GPS data can be assigned to an OCAD symbol. OCAD creates unsymbolized objects if no cross reference table is selected.

Each line of the cross reference table consists the OCAD symbol number and the Garmin symbol name.

Example of cross reference table:

535.0 waypoint dot

536.0 campground symbol

540.0 scenic area symbol

• Create: Select the waypoints and tracks in GPS data field and click this button to create OCAD objects from the selected GPS data.

A popup menu appears when clicking the Right mouse button in GPS data field. You can clear the list, select records or unselect records.

Import from GPS Settings

In this dialog box you can make the setting for the GPS data import. Verify also your setting in GPS device (e.g. data format: GARMIN)!

• Port: Choose the port where the GPS device is connected.
• Speed data import: Choose the speed of the serial port. Garmin defines 9600 bps.
• Coordinate system: Click the Change button to select or change the coordinate system. The Coordinate system dialog box appears.

Import from File

Choose this command to import a GPS data file to the current map. The Load GPS data from files dialog box is displayed. Initially all importable GPS data files are listed. The following file types can be imported:

GPX files

FRWD files

NMEA files

The waypoints and tracks from the imported file are listed in the Import data from GPS device dialog box.

OCAD objects

• Set label: Check this option to create also text objects with the name of waypoints and tracks.
• Assign Symbols: Check this option to assign a specified symbol to the imported objects. Otherwise OCAD will create unsymbolized objects.
• Create: Select the waypoints and tracks in GPS data field. Click this button to create OCAD object from the selected GPS data.

A popup menu appears when clicking the Right mouse button in GPS data field. You can clear the list, select records and unselect records.

GPS Map Offset

This dialog box appears if the GPS coordinates are out of the maximum map size.

Coordinate system If you work with GPS you must select a coordinate system. Click the Change button to select or change the coordinate system. The Coordinate system dialog box appears.

Offset Choose here whether you want to change the OCAD real world coordinates or to keep the existing ones.

New offset: Choose this option if no real world coordinates are defined for the map. OCAD already proposes reasonable values. You can leave theme unchanged.

Existing offset and angle: Choose this option if the map already has real world coordinates and you want to fit the imported objects to the existing coordinates.

Laser Distance Meter

Read more about using "TruPulse 360/360B" laser range finder

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