I have navionics premium, and noticed on navionics web app how much more detail and creeks beds, structure, ect it shows.. what I am trying to find out is if navionics platinum shows the same information as what is shown on navionics web app.

The Navionics Hotmaps Premium cards were discontinued in 2015 and replaced by Navionics+ regional cards.
Navionics Platinum+ is a current product.

Both Platinum+ and Navionics+ cards are updateable so what you see on the Navionics website's Chart Viewer and with the mobile app can be on those cards if you do an update.

A new purchase includes a year of Freshest Data Updates and can be renewed annually if you want to keep current.
Navionics does up to 5000 additions/updates daily around the world.
Check the Chart Viewer occasionally to see if any additions are what you want and do an update to get them.

so If I purchase this card

https://www.navionics.com/usa/navionics-plus-us-south-1.html

it should have the detailed information that I can view on navionics web app already pre loaded on the card, with no updates needed for what is presently viewable on web apps?

I read on another forum that Navionics plus is not regional, but the card in the above link states that it is regional . the south? thanks

The web app is current, the map card has the data that was current when it was made. The data can be months or years different.
A new card has to be registered to start the Freshest Data subscription. Update it when you do that.

There has been several versions of Navionics+. The first one was 2GB with no maps, you select where and how much data to download up to the 2GB capacity and can delete data to download other locations. It’s different now since Garmin bought the company.

I

The card will be mostly up to date but depending on when it was drawn you may need to update it to be "current" as of the day you update the card. It is easy and does not take very long unless you choose to update the entire map, which once you have done that a few times you will learn to just update the lake(s) or area you are planning to go to.

You will like the card.

THANKS ! I was shocked at how many old roadbeds, underwater culverts, creek channels, old house foundations, ect is on a lake I fish that I didnt know abt until I looked at navionics web app. I think having the navionic plus or platinum is going to open up a whole new capability for my winter fishing strategy.
winter crappie fishing is all about finding the creek channels, ledges, drop offs, ect.

Re-surveyed bodies of water have more info using unit settings than the web app shows . This is Kentucky Lake, Lake Fork is done this way also----