Do you want just a straight line between your lat lon points or do you want a route drawn following a path, track or road between each lat long point?
Give this program a try.
http://www.gpsvisualizer.com/convert_inputEasiest way would be to paste your data as comma separated text into the box then select the 'gpx' button, then convert.
If you have a very large number of lat long points it may be easier to get them into a spreadsheet to get the format done and then export to csv and pasting it in the box.
http://www.gpsies.com/convert.do is an easy way to convert lat, long points to gpx track or to way points.
Form is simply as follows in a text file for the input.
lat,lon
-27.13639,152.98156
-27.12023,152.99460
(It is also an excellent program for creating tracks)
If you instead want a route drawn between your points, you could type them into Graphhopper as in the following example that will plot the way using the openstreetmap data and you can save as gpx. At the top of the page you can change the mode from a vehicle to walking to cycling and the route will change to suit in most places if more suitable routes are available.
https://graphhopper.com/maps/?point=-28 ... =OmniscaleGoogle maps also accepts input of lat long points into the boxes when you select the directions button. It changes the lat lon coordinates to text but uses the point data you entered and their routing data to show the route on the map ( eg
https://www.google.com.au/maps/dir/-27. ... 440916!3e2 ). If you select 'details' you will see a share button and on selecting it you will be given a url of the route.
If you paste that url into the url box at this site
http://www.gpsvisualizer.com/convert_input , select the 'gpx', button and then convert. Near the top of the next you are given a gpx link to download.
And finally to view your gpx file, use this site
http://www.gpsvisualizer.com/map_input? ... width=1200Load your gpx files at the 'Upload your GPS data files here' section and 'Draw the map'
In the top right corner you can change the background map.
If all is well, drag and drop the file from your pc/mac to the GPX folder in the Garmin, go to the 'track manager' to find it, view on map, show on map, or select 'where to?', then 'tracks' and select the one you want and select 'GO'