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dataFiles Parameter

There are four different types of data files which javAPRS can display: NMEA, TNC, HST, and NADSD. Click here to learn about network connections. javAPRS differentiates them based on the suffix, .nmea, .tnc, .hst, or .nad. An unlimited (except by memory) number of files may be opened. Each data file is loaded by a separate thread, and proceeds independently. Data files must be numbered sequentially starting with 1.

<PARAM name = "dataFile1" value = "trip.tnc">
<PARAM name = "dataFile2" value = "keys.nmea">
<PARAM name = "dataFile99999" value = "marathon.hst">

NMEA files consist of the stream of data coming from a GPS. javAPRS understands the $GPRMC, $GPGLL, and $GPGGA sentences, others are ignored (same for raw GPS packets in other modes). Each position is plotted on the map as a dot, and the playback of a sequence of this data results in a moving line.

TNC files are the raw data sent from a TNC. Consult the APRS documentation for explanations of the various data formats. This format is the log file saved by MacAPRS and WinAPRS. If you do use files in this format, keep in mind there is a tremendous amount of duplication and non-positional report information that comes of a typical VHF APRS LAN. The display of such a file is greatly enhanced if the file is manually edited to remove this redundant and extraneous material. In this example, the original log file was nearly 700k, but after editing it is only 100k.

HST files are the history files produced by the dos version of APRS. These files are typically very small, as extraneous and redundant material is removed by APRSdos.

NASDSD files were created by TAPR to display digis, nodes, BBS's, etc. The format of the file is:


The latitude and longitude are formated as direction,degrees,minutes: N3316.04
type is one of the following: ROSE,TCP,NET,NODE,SWITCH,RPT,APRS,BBS,DIGI
system & protocol are strings that can be used as a filter.

Data files can be placed within the javAPRS folder containing the class files. If they are there, only the file name need be specified, as in the examples above. If the files are anywhere else, the the full URL must be given:

<PARAM name="dataFile1" value="">

<PARAM name="fileReload1" value="600">

This allows you to periodically reload the data file. This is useful where the data file is uploaded to the server automatically at defined intervals. The time between reloads is specified in seconds.

<PARAM name="sleep" value="500">

This value slows the display of icons (500 = .5 seconds).