Maps vanishing with new installs?

[Staccat0]

I'm new at this, so please bear with me.

I downloaded a topo map and trail map just fine and installed them with mapsource on my Nuvi 255w just fine... or so I thought.

Unfortunately each time I download one, the other vanishes...
Whats going on here?
I read the tutorials but they are pretty bare bones...

[Boyd]

That's the way mapsource works. It creates a file named gmapsupp.img which you will find in the \Garmin folder on your GPS. Each time you send a new map to the GPS, it replaces the existing gmapsupp.img file.

You can have a second map file on a memory card in your Nuvi, and mapsource will let you choose the memory card as a destination.

If you need more maps at the same time, the trick is to use mapsource to select all the portions of the different maps you need. Choose the first map, select the parts you want, then use either the dropdown map menu or "switch to product" menu to choose the next map, select the parts you want of it and repeat as needed.

You will see a list of all the map tiles you have selected in the left-hand pane. When you send these to the GPS, you will have all the maps combined in a single file, and can press Menu > Tools > Settings > Map > Map Info to select the one that you want to display.

[maps4gps]

You must send all the data to the GPSr at one time.  In MapSource select what you want from one mapset; then select from a second mapset; etc.; only then do you send the data to the GPSr.  Any gmapsupp.img on the GPSr will be overwriten.  The GPSr only recognizes one gmapsupp.img file.  This file needs to be recreated each time you want to add (or remove) any map data from it.
FYI - that is step 8 in http://www.gpsfiledepot.com/tutorials/how-to-load-maps-on-my-garmin-gps-unit/

[Boyd]

The GPSr only recognizes one gmapsupp.img file.

As mentioned above, it will actually recognize two gmapsupp.img files. One in the Garmin folder in internal memory and a second in the Garmin folder on a memory card.

[maps4gps]

Boyd is correct.  I should have stated it as one gmapsupp.img file per memory location.

[Staccat0]

ahhhh... I see. Missed that little bit (or rather didn't quite grasp its signifigance)
anyway, thanks so much for the help folks!

[DrRon]

OMG!  I've been struggling with this same problem on my 60CSx and finally read the help file on MapSource and discovered what you are saying here!
I really can't believe this.  I've got a 4G micro card in my unit and need to add maps and tracks and waypoints to it all the time.
It looks like MapSource will let me transfer data other than maps without erasing the maps, but will erase all existing other data before transferring the new data.
So, it looks like I am going to have to be careful to build two different MapSource database files, one with only maps and one with only other data.
The real kicker here is that if I want to add any kind of map update, I am doomed to the long time required to completely rewrite the entire data card.  What a poor design approach!

[DrRon]

Now, with regard to this topic, but focusing on MapSource, it easy to drag the map selector over a map to select what I want to load.
But - do I really have to unselect each map box one at a time to return to the original condition?
Is this just another design element to challenge my efficient use of time?

[Seldom]

The real kicker here is that if I want to add any kind of map update, I am doomed to the long time required to completely rewrite the entire data card. 

You can cut your transfer time significantly if you remove the card from the 60CSX and use a USB2 card reader.

[maps4gps]

The real kicker here is that if I want to add any kind of map update, I am doomed to the long time required to completely rewrite the entire data card.  What a poor design approach!

That has been an issue for years.  The CO, OR & DK models and perhaps some NUVI's do not have this issue.  I have not heard, but would expect the new 78 and 62 models to also allow multiple .img mapset names.

[maps4gps]

... focusing on MapSource, it easy to drag the map selector over a map to select what I want to load.
But - do I really have to unselect each map box one at a time to return to the original condition?

No. Simply select everything in the large window on the left which list the quads/tiles selected and right click and delete them.  They will only be deleted from the selected list, not from the map window.

[DrRon]

Got it.  Thank you so much.  I knew there had to be a simpler way but just am too new at this to know.  That's the beauty of this forum and the appreciation I have for you experts.  Thanks again for your generosity of time and talent.