Loading Multiple Maps on Lowrance

[siiverlce]

Salutations, everyone! I hope I'm not a pain. 

I love the Photo Overlay and Shaded Relief method of processing maps now, and I was wondering. Is there a maximum number of maps that you can switch between in a Lowrance system?

For example, I am considering using satellite images from the "past/history;" and this would allow someone to look at a day that had low tides. It would be easier to make multiple smaller maps with these past images, so I am wondering if there's a maximum. Would the system not handle 20 different maps on the SD card?

This could allow someone to travel to different areas, and they could load up the past image for their current position.

I hope I am getting my thoughts on this idea across coherently.

[gregory]

If you are using different description strings for each time offset, it depends on the size of the card and the available chart plotter resources.  Shaded relief isn't too hard on the resources so probably more of a card size restriction.  Before image compression, it's 1/2 byte per pixel plus around 1% overhead.  After image compression (available in the beta IMC), it's hard to say but typical compression is around 40% of that 1/2 byte number and substantially better if there is a lot of repetition.