[johannetje2]

Jefff said the textdraw AltitudeString must been showed. But that's a string, not a textdraw.

Код:

TextDrawSetString(Altitudemeter, AltitudeString[playerid]);
    TextDrawShowForPlayer(playerid, AltitudeString[playerid]);
    }
    else
    {
        TextDrawHideForPlayer(playerid, AltitudeString[playerid]);
    }

^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

What to do with the format?

Код:

format(AltitudeString, sizeof(AltitudeString), "Altitude: %.2f meters", z);

If i do what Jefff said, i receive 11 errors.