I know this is a very basic question but I just got my first sidescan. I've been away from the technology the past few years since the birth of my daughter. I've got a lot of catching up to do!

So which card works best to show contours and lake detail. I will strictly be on the more popular N. Texas lakes

Humminbirds can use Lakemaster and Navionics digital mapping.

The product that is best for you is the one that has the waters you fish and has the detail you want.

You can download the Lakemaster lake list from the Humminbird Lakemaster website and look for waters that are Lakemaster High Definition Survey-- those a very good.

You can view the current maps on the Navionics website's Web App. That is updated daily. If that has what you want, you can get the exact maps by updating a Navionics card you purchase.
Navionics Hotmaps Platinum South Region and Navionics+ would be the two choices.
Both of those can have the user generated HD contour mapping layer called Sonar Charts downloaded when doing an update.

Thanks. That's alot of info. I appreciate the time

Best is both. If only one then research the lakes you fish and see which has the best for the lake. I like lakemaster because of the functions like changing the water depth to match the current lake conditions but navionics has more detail.

Hey there, K.D. I have an 898c SI and I use the Navionics map card and it's great. The depths on the contour lines might be off sometimes (even with the lake at full pool), but I've found the locations of the lines to be very accurate.

For example, if I see that the west side of a hump has a sharper dropoff than the other sides, when I drive over it with the sonar, I find the map to be accurate.