qtVlm is navigation software designed expressly for sailors.
It is also a free weather grib viewer that accepts all kinds of gribs.
It can read and display maps in various formats

  • Vector charts (S57 and S63)
  • Raster charts (kaps, geotiff, etc)
  • MbTiles charts
The StarPath team has put up many videos how to use qtVlm on a   YouTube playlist.

With GPS2IP configured as a Socket - the two applications can easily communicate with each other.
Instructions for setting up GPS2IP in socket mode follow.

Configure GPS2IP for Socket Mode

When GPS2IP is operating as a socket, it waits and listens for something to connect to it.
Many different devices can connect to GPS2IP simultaneously, and when it transmits data, it will transmit to them all. In this situation, it is easy to receive the same data on different computers on your network.

Step 1

Go into Settings

Scroll down to the bottom.
Select Socket mode.

Step 2

Press     to Enter Socket Settings

Here you can see and edit the Socket Port number.
In this example, the socket port is 11123.

Select your preferred port number, and hit Done to exit.

Hit Done again to exit Settings.

Step 3

Verify Socket mode

You can see that iPhone Server IP can be seen on the front.
Also, that the Port Number you selected in Step 2 is shown.

Step 4

Enable and Connect

Enable GPS2IP with the switch at the top.
If a client connects, the Connections value increases.

Here, we can see one client is connected, and receiving NMEA data.

Configure qtVlm

Once GPS2IP is correctly configured in socket mode, and both devices are on the same network, then it is merely a question of setting up qtVlm to connect to the GPS2IP socket.

Step 1


MENU: QtVlm > Configuration
(or Alt-x)

Step 2



Step 3

Enter GPS2IP details

  1. Enable Automatically start NMEA acquisition at startup for a more pleasant experience.
  2. Enable one of the TCP servers, and enter the details on the GPS2IP front screen
    (In this example the GPS2IP iPhone Server IP is, and the Port is 22105).

Step 4

Restart qtVlm

Click OK to accept the changes, and restart qtVlm.
(Remember to enable GPS2IP, too!)

You position should automatically show up in qtVlm.

If you're still lost, please Get in touch - we'll be happy to help...