Free online PLT to KML converter

People convert PLT files to KML when a GPS track or route must be opened in Google Earth, shared as a map, or imported into GIS software. The correct method depends on whether the PLT file is an OziExplorer coordinate track or an HPGL plotter drawing.

What the PLT format is

PLT is an ambiguous extension. OziExplorer uses .plt for GPS track files containing latitude, longitude, and track metadata. GPS devices, navigation software, and mapping applications may create these files.

CAD and plotter software also uses .plt for HPGL instructions such as pen movements, usually generated by programs including AutoCAD and other engineering or sign-making applications. HPGL PLT files normally contain drawing coordinates rather than geographic latitude and longitude, so they cannot be converted directly into a correctly positioned KML map without georeferencing.

What the KML format is

KML is an XML-based geographic format supported by Google Earth, Google Earth Pro, QGIS, ArcGIS, and many GPS applications. It stores points, lines, polygons, labels, styles, and coordinates in longitude, latitude, and optionally altitude order.

KML is suitable when the result needs to be viewed over satellite imagery, shared as a map, or edited as geographic features. Its compressed counterpart, KMZ, packages the KML and related resources into a smaller ZIP-based file.

How to actually convert PLT to KML

For an OziExplorer PLT track

1. Open the file in a text editor and check that it contains an OziExplorer header and comma-separated coordinate records. Do not use this procedure for an HPGL file beginning with commands such as IN, PU, or PD.
2. Install GPSBabel, then run:

gpsbabel -i ozi -f input.plt -o kml -F output.kml

3. Open output.kml in Google Earth Pro or QGIS and check that the track is in the expected location.
4. If the source contains multiple tracks or waypoints, inspect the generated folders and placemarks separately; GPSBabel may preserve them as different KML elements.

GPSBabel can also be used through its graphical interface: select the OziExplorer input format, choose the PLT file, select KML as the output format, and specify the destination filename. On 101convert.com, you can convert a compatible PLT file to KML for free without installing software; this applies to geographic PLT files, not ordinary HPGL plotter files.

For an HPGL or CAD PLT drawing

First open the file in the originating CAD or plotter application and determine its coordinate system, units, scale, and drawing origin. Export it to a GIS-readable format such as DXF, then import it into QGIS or another GIS program, assign the correct source CRS, georeference it if necessary, and use Export → Save Features As with KML as the output format.

If the drawing has no known geographic control points or coordinate reference system, the resulting KML can only be positioned arbitrarily. Converting pen coordinates to longitude and latitude without georeferencing produces a file that may open successfully but appears in the wrong location.

Quality and compatibility limitations

OziExplorer PLT coordinates are geographic, but the file may contain limited metadata. Verify the datum, especially if the track was created with older mapping software; a datum mismatch can shift the result by tens or hundreds of metres. KML normally uses WGS 84 coordinates, so reproject the source when its datum or CRS differs.

Altitude handling is also format-dependent. A PLT track may contain speed, altitude, or date fields that are not preserved as KML elevation unless the converter maps them explicitly. Check the KML in Google Earth using the elevation profile when vertical accuracy matters.

Large tracks can produce bulky KML files. Simplify or filter unnecessary track points before export if the destination application has performance limits, but retain the original PLT as the authoritative source.