GetGPSInfo()

Summary

Gets a reading from a GPS device.

 

Syntax

GetGPSInfo()

 

Returns

In case of a transient error (e.g., a timeout when reading from a GPS device), a one-element array is returned, containing a string describing the error. Otherwise, an array of eleven elements is returned, describing the current GPS reading. If particular information is missing, that field is null, otherwise the elements are:

 

Element	Type	Contents
1	Integer	Longitude (in millionths of degrees)
2	Integer	Latitude (in millionths of degrees)
3	String	Time in the form HH:MM:SS.uuu (hours, minutes, seconds and milliseconds)
4	String	Date (DD/MM/YY)
5	Real	Course in degrees true north
6	Real	Speed (over ground) in miles per hour
7	Real	Altitude in feet
8	Real	Course in degrees magnetic north
9	String	Text describing the status of the device
10	Real	Horizontal dilution of precision
11	String	Text describing the status of the device

 

Notes

• A GPS device must be initialized with StartGPS().

• The data from the device must be in the NMEA 0183 format.

• If only a partial reading is obtained, some of the fields may be null. Some GPS receivers never provide some of the information in this list; e.g., some devices use only degrees true north, others give magnetic north, and a few give both.

• A typical receiver only sends data once per second, so frequent readings result in transient timeout errors.

Example

// Most common settings

options = {{"Read From", "\\\\.\\COM1"}, {"Baud Rate", 4800},

     {"Data Bits", 8},{"Stop Bits", 1}, {"Parity", "None"}}

StartGPS("Serial Port", options)

dim pos[10]

for i=1 to 10 do

     gps_data = GetGPSInfo()

     if gps_data.length = 1 then

          ShowMessage("An error while reading: " + gps_data[1])

     else if gps_data[1] <> null && gps_data[2] <> null then

// Store the location as a coordinate

          pos[i] = Coord(gps_data[1], gps_data[2])

end     // for

StopGPS()

 

Error Codes

Error Type	Meaning
Error	No GPS device has been initialized, or a fatal error occurred while reading from the device
EndOfFile	Reached the end of the playback file (not applicable when reading from serial ports)

 

See Also

Function	Summary
StartGPS()	Initializes reading from a GPS device
StopGPS()	Closes a GPS device