Sd/mmc Card Info Please

[+Overfloater]

I am buying a Lawrence H2O plus, and am very new to the expandable memory cards.

 

I read in the mapcreate literature that you can only register 5 cards. I am not sure I like this. My question is can you treat these cards like a regular PC floppy disc? For instance: can you save a map to a card, then later erase that map and put a new map on the card? And, does the gps read the cards like a floppy when you are in the map mode, or does the entire card get downloaded to the gps and it works like a hard drive?

 

Also, if you buy a very large memory card and fill it up with maps, does this effect the way the gps operates in the field? (slower?, eats batteries more?, etc.) If this is the case then I only want to save my immediate hunting/geocaching area for speed and battery life, but if the cards cannot be overwritten then I will have 5 cards used up in one year.

 

Finally, I am glad I found this forum. I have been researching what gps I want to buy for two weeks. I had an old-timer Eagle explorer(lowrance i believe) and it worked very well up until recently when it stopped locking in as fast as it used to. I probably had that gps for 8 or 9 years??? That's pretty good.

 

thanks for any help

[+PDOP's]

You'll find answers for some of your questions in this thread and in this thread.

Edited December 11, 2005 by PDOP's

[+kb7sei]

Okay, I have an H2O so I can help you out here. The threads mentioned are usefull as well, but you want really basic info.

 

The cards are flash memory, so they are eraseable and re-writable. Most flash devices can be re-written up to 1 million times. So yes, they are a lot like a really big, really reliable floppy disk.

 

The 5 card limit is annoying, but not so bad since you can erase the card and put different maps on it. You can also buy a large SD card, I use a 1GB, and put a LOT of maps on it. It does slow down the GPS a little, but not enough to cause problems. And the extra data sure is nice. It does not seem to affect battery life significantly.

 

The card data does not get copied to the GPS unit. The GPS reads the data as it goes. So if you remove the card, the GPS won't be able to use those maps anymore. However, this is NOT the case with waypoints. You must tell the GPS to load the waypoints before you can use them. It won't look for them for you, and can only hold 1000 at a time. This limit is for normal waypoints only, tracks have thier own memory. The good news is that you can have as many files on your card as will fit, so you can just erase all data, then load the files you want as needed. You can also write the data back out to the SD card so you won't lose anything.

[+Klemmer]

The Magellan Meridian series, and Explorist series (the ones that have SD card slots) work about the same way, but don't have any 5 card limit that I am aware of. The process of READING or WRITING a file might take a LITTLE extra battery juice, but the memory itself is non-volitile, and doesn't eat any battery just siting there.

 

P.S. Very happy with my Magellan Meridian Platinum.

[+user13371]

...Magellan ... works about the same way, but don't have any 5 card limit...

I believe there's at least one other BIG difference that I'm aware of between Magellan and Lowrance implmentation of the SD cards.

 

Let's say you load maps for several regions. On the Lowrance, if you are in an area covered by one of your detailed maps, it shows you that map data - and if you move from the coverage area of one map to another, the Lowrance simply shows you the correct map for your area. This seems obvious, but...

 

On the Magellan, you have to TELL the unit which map file to use - and if you leave the coverage area of one detailed map and enter another, you have to user a menu command to have it change the active map.

 

At least that's how I remember my Merdian worked. Have they changed this?

Edited December 13, 2005 by lee_rimar

[+Overfloater]

Thank you everyone. kb7sei you hit everything on the head.

thanks again