Upload/Download Data from popular Global Positioning System handheld receivers.
Copyright 1996 James Associates, All Rights Reserved.
This version (0.4b7 Beta) only may be distributed freely, but only if this documentation and the attached waypoint file and its documentation are included in their original form. It may not be distributed as part of a commercial product, except for products which consist of a compilation of freeware and shareware software.
This software program must not be relied on as any part of a primary means of navigation. It must not be used in a way where your safety or your property depends on its successful operation. It may have bugs which we will try to fix if you notify us, but we accept no liability for anything which happens because this program does not perform correctly. These statements will be interpreted under United States and Colorado law. Your use of the software signifies your agreement with these conditions.
Garmin GPS 40/GPS 45/GPS 90 Communications for the Rest of Us
Based in part on MacGPS45 source code and documentation donated to the public domain by John F. Waers.
Thanks to Daniel Ebneter for documentation and sample code for the Swiss grid to/from CH-1903 conversion. Thanks to Jaime Villacorte for debugging help.
Beta Version 0.4b7
The 4 additional datums which are in the current models of the GPS 45 are now included in MacGPS. Because of this change, you will probably have to reset your datum choice in the Preferences dialog box the first time you use this new version if you are upgrading from an earlier version.
The German Grid and the Swedish Grid have been added to the position format options.
The code for Transverse Mercator conversion, including UTM and the national grids, is now more accurate.
The Preferences file is compatible with MacGPS Pro 1.3.x.
Fixes a rounding error on reading of file entries between 0° and -1° in the DMS and DMM formats.
Adds an alert when you try to open (for a transfer) a file which is already open in another program.
Fixes a problem with Transverse Mercator conversion on 680X0 processors.
Fixes a compiler error which caused a crash on 68000 (Mac Plus, PB 100) processors on the British and Irish Grid conversions.
Now runs on all systems from 6.0.5 up, and on all Mac processors, including 68000-based systems such as the MacPlus and the PowerBook 100. (If you find an exception, please let us know).
A Fat Binary (Native code for both 680X0 Macs and PowerPC Macs)
(Use "Stripper", available from the info-mac mirror sites, to remove
unneeded code if you are tight on disk space.)
January 8, 1996
Program Features
• Upload and download waypoints, routes, track logs and satellite almanac data. All but the almanac data are saved in editable, tab-delimited text files, allowing easy entry of waypoints and routes using a text editor. The waypoint, route and track log files may be easily imported into a graphing/analysis program for graphical display.
• User selectable map datum, allowing coordinate conversions to the same set of 106 map datums within the GPS 40 and the GPS 45.
• User selectable output file position format, with latitude and longitude in degree/minute/second, degree/decimal minute, or decimal degree format, or UTM, British, German, Irish, Swedish, or Swiss grid coordinates. Latitude and longitude values are shown as negative values for southern latitudes and for west longitudes.
• Real-Time data (NMEA 0183) capture and/or display utility.
Hardware Interface
This is the hardest part of getting your Macintosh to talk to the GPS receiver. The GPS receiver must be connected to the Macintosh modem port (or printer port if the modem port must be in use for something else). Garmin makes a power/data cable for the GPS 45 (P/N 4520, $21.95 from James Associates), and a data cable for the GPS 40 or GPS 45 (P/N 4042, $17.95 from James Associates) which may be wired to a Macintosh mini-DIN connector. Connect the wires as follows (see Inside Macintosh, Volume IV, page 248 for Macintosh connector details):
GPS 40, 45 or 90 Macintosh Macintosh connector description with key up
_____________ ______________ _________________
Data Out (Brown) Receive Data (5) pin in same horiz. plane as center pin, not as close
Data In (White) Transmit Data (3) pin in same horiz. plane as center pin, closest
Ground (Black) Ground (4) centermost pin
Power (+) (Red) No Connection No Connection
The GPS 40/GPS 45/GPS 90 data out is a 0 to 5 volt signal which will drive most RS-232 ports (RS-232 transition levels are typically about 1 to 2 volts). The Macintosh will not respond to this signal if the Receive Data + (8) line is grounded. Good results are obtained on most computers by simply leaving the Macintosh Receive Data + open, but this may not work with all computers. It may be necessary to bias the Receive Data + line at some positive voltage (about 3 volts), or to put a 10K to 20K ohm resistor between the brown and black leads from the GPS connector.
While you’re at it, you can also connect a DC power supply (6 to 40 volts DC for the GPS 45, 7 to 8 volts for the GPS 40) between the Garmin Power (red, positive) wire and the Ground (black, negative) wire, and save your batteries. Any adapter rated at 7 to 8 volts with an output current of 250 mA or more should work.
Menus
File Menu/Close
Stops the collection of Real-Time data. The close box on the window also works to stop the collection of Real-Time data.
File Menu/Preferences…
Selecting the Preferences… menu choice brings up a dialog box:
Serial Port
Use the modem port unless you absolutely cannot. On PowerBooks, you must choose "External Modem" from the "PowerBook Setup" Control Panel. On most PowerBooks with only one physical port, the modem port must be chosen.
If you must use the printer port, do not run any other program which accesses a disk or other I/O device at the same time you are transfering data with MacGPS, or some of the data will probably be lost. AppleTalk must be OFF to use the Printer Port for MacGPS.
Selected Datum
Select the desired map datum from the list. The following information is displayed for the selected map datum:
ellipsoid name
a = semi-major axis of reference ellipsoid, meters
f = ellipsoid flattening
x, y, z = offsets from the WGS84 ellipsoid center, meters
The datum selected here affects the position data in the waypoint, route and track log files; the NMEA data is referred to the map datum selected in the GPS 40 or GPS 45.
Output File Position Format
Select one of the nine available file formats for position data. These buttons determine the format of the data stored in the waypoint, route, track log and real-time files, and displayed in the real-time output window. The degree/minute/second and the degree/decimal format contain the punctuation as shown, and thus probably cannot be imported into other programs. UPS conversions for the polar regions (>84°N or <80°S latitude) do not agree exactly with that in the GPS 40 and the GPS 45.
Data File Creator
The output data file has a type of 'TEXT', but the creator is user selectable. Some common creators are 'ttxt' for SimpleText, 'R*ch' for BBEdit, 'XCEL' for Excel, etc. The default is 'GpSj' for MacGPS.
UTC Offset
Enter the difference between your local time and UTC, or set this value to zero if you want to use UTC time stamps in the data files. This offset corrects the UTC time to local time for time stamps in the Waypoint, Route, Track Log and Real-Time files.
File Menu/Quit
Immediately stops the MacGPS program.
Transfer Menu/TO GPS Receiver
Almanac…
Routes…
Track Log…
Waypoints…
Transfer Menu/FROM GPS Receiver
Almanac…
Routes…
Track Log…
Waypoints…
Select one of these hierarchical menu items to transfer data from a file to the GPS 40/GPS 45/GPS 90, or to transfer data from the GPS 40/GPS 45/GPS 90 to a file. When any of these hierarchical menus is selected, the program reminds you to set the GPS 40/GPS 45/GPS 90 to the correct protocol.
Almanac
The almanac data is stored as ASCII hexadecimal characters representing the data stream actually sent to/from the GPS 40/GPS 45. While the program can send almanac data to the GPS 40/GPS 45, under most conditions it is not appropriate to do so. Sending obsolete almanac data means that the GPS unit will not be able to find the satellites, and you will have to switch to "Autolocate" mode to make the unit useful again.
Route
Each route is identified by route number and name, followed by the waypoints comprising that route. When downloading route information to the receiver, new waypoints are created as necessary, and existing waypoints are overwritten if the new waypoint has the same name.
Track
Each of those points in the map display is a time stamped position. When loading a track log into the GPS 40/GPS 45/GPS 90, the receiver ignores the time stamps.
Waypoint
Each waypoint includes the name, position, description and time stamp indicating the waypoint entry time.
Real-Time Menu/Display Current GPS Readings
Select this item to display real-time position data from the GPS 40/GPS 45/GPS 90. When this item is selected, the program reminds you to set the GPS40/GPS 45/GPS 90 to the correct protocol. Click in the dialog close box to end the display.
Real-Time Menu/Collect Current Readings
Select this item to capture real-time position data from the GPS 40/GPS 45/GPS 90 to a file. When this item is selected, the program reminds you to set the GPS40/GPS 45/GPS 90 to the correct protocol. Every 2 seconds, a position point is written to a disk file. The only limit is the amount of disk space available. If you are using a laptop and you don't want your hard disk to be running continuously while you are collecting data, choose a file on a RAM disk to write the data to. Under system 7, you can set up a RAM disk using the Memory Control Panel.
File Formats
Each real-time, waypoint, route, and track log file starts with the following header line, which contains three fields which are used by the program when downloading the file information to the GPS 40/GPS 45/GPS 90. The format field ("DDD") may be either "DMS", "DMM", "DDD", "BNG", "ITM", "SUI", or "UTM", depending upon the format of the file position data. The UTC time offset ("-6.00") is used to correct file time stamps to UTC, and the datum number ("061") is used to correct file coordinates to WGS84 coordinates for transferring data to the GPS receiver. When editing the file, this line should not be altered.
Format: DDD UTC Offset: -6.00 hrs Datum[061]: NAD27 CONUS
The route file contains both route and waypoint records. The route record starts with the letter 'R', followed by the route number and the route name. Each field is separated by a tab (indicated by the '◊' letter below). If the route has no name, the name is stored as 16 underscore characters.
R◊1◊________________
The track log file contains track records in the following format, with the '◊' character designating a tab character. Each track record starts with the letter 'T'. This example shows each of the four position formats that may be selected in the Preferences menu. Note that the UTM zone number and letter are separated by a tab, as are the other fields. The date and time in the time stamp field are separated by a space.
T◊09/09/1994 20:03:49◊40.1780207◊-105.0901666
T◊09/09/1994 20:03:49◊40°10.681'◊-105°05.410'
T◊09/09/1994 20:03:49◊40°10'40.9"◊-105°05'24.6"
T◊09/09/1994 20:03:49◊13◊T◊0492323◊4447310
The waypoint file contains waypoint records in the following format, with the '◊' character designating a tab character. Each waypoint record starts with the letter 'W'. This example shows each of the four position formats that may be selected in the Preferences menu. Note that the UTM zone number and letter are separated by a tab, as well as the other fields. The date and time in the time stamp field are separated by a space. The name field may be up to 6 letters, the description field up to 16. All letters must be upper case.
If you would like you may add an additional comment field of your own to file entries using a text editor or a spreadsheet. Simply separate your comment field from the last "official" field with a tab character. This field will be ignored when uploading the file to the GPS receiver. The total line length must be less than 255 characters.
W◊PLATT◊6096 BASELINE RD◊07/28/1995 20:12:54◊40°00.202'◊-105°12.723'◊PLATT MIDDLE SCHOOL, BOULDER VALLEY
The almanac file includes 32 records, each with 42 bytes represented in ASCII hexadecimal format, containing the satellite almanac data for each of the 32 satellites.
Future Directions
There is a conflict with After Dark, resulting in a system crash if the screen saver is activated when the Preferences dialog is displayed.
Waypoint, route, and track log files. The routines used to read these files are not very robust, and simple mistakes in the text files can cause weird errors.
See the enclosed description of MacGPS Pro for more available features.
I hope that you enjoy using this program. Send any suggestions or comments to:
