Thread: Creating my own JNX map for Etrex 20

Thanks for your links. I have already made a start. My project involves converting a few of the Nepal Topo maps downloaded from here:

Code:

Please Login or Register to see the links

and converting them to *.jnx to load into an Etrex 20.

I have applied the jnx patch to the Etrex successfully. My first problem was finding a GUPDATE.GCD file to patch since none was present in my device. Apparently it is deleted when the last update installs and since the firmware was already up to date I could not download another update from Garmin. Managed to find an alternative here:

Code:

Please Login or Register to see the links

I downloaded eTrex20_30_Webupdater__430.gcd and extracted into the Device:\Garmin folder. Do not restart the device. The update file must not be used until it is patched. Remove any existing *.jnx files from the Birdseye folder. eTrex20_30_Webupdater__430.gcd was renamed to GUPDATE.GCD, Then it was just a question of using the jnxpatcher and instructions here: [Only registered and activated users can see links. ].

Needed to use the option to reset the update no to 431.
Used the trial jnx file in the thread to confirm it was working.

Creating my own JNX files is being done using MAPC2MAPC:

Code:

Please Login or Register to see the links

Registered copy gets rid of all the red crosses - happy to part with £15 for the privelege.

Some problems calibrating the maps initially, using Lat/Long and WGS 84 projection . They were appearing about 250m out of position when compared with Google Earth.
Now have a sample successfuly calibrated using the Google Earth method here:

Code:

Please Login or Register to see the links

Last thing was to adjust the JNX scale to control the zoom level at which the map appears, using JNXSCALE from here:

Code:

Please Login or Register to see the links

Scale was set to 2388 which makes them appear at about the correct resolution on the device. Seems a bit random though.

I have around 10 maps I intend to convert. They appear as individual jnx files in the device and can be separately turned on and off but I might merge them when they are all done if I can figure that out. Also may be useful to have different levels of detail and different zoom levels but I dont think MAPC2MAPC does that so maybe a different utility would be needed. More to learn.

Sorry if this lengthy post is in the wrong place.



Please code all external links as per [Only registered and activated users can see links. ] to avoid refback!