There is alot of talk about Down imaging/Down Scan vs Side Imaging/Side Scan not only when to use them but how you use them. It's impossible to cover everything that pertains to these two different types of technologies (Ie Down Imaging vs Side Imaging) as book can literally be written about the two in itself. There is no doubt that seeing fish on your graph and catching them are two completely different things. Many have confirmed what I have always said about DS and DI. They are great if you want to look at structure and get target seperation from a downward view BUT if I had a dime for every fish I spooked by running over it I would be rich. I wish I took images of fish in structure then to go back over it find that the fish are gone because they got spooked. Honestly SI is still king and always will be king (for the time being) in terms of finding fish, brush locations and most importantly time management. If your a shallow water angler DI isn't no where as useful as SI. SI is STRONG in BOTH Shallow and Deep water applications. Having said that BOTH technologies have their pluses and minuses.
Here is one method of MANY in why I feel like SI is superior in fishing and marking a piece of structure.
My methods for fishing open water structure is as follows.
Find it on Side Imaging and mark a waypoint in the center of the tree.
Then mark a waypoint at the TOP of the tree and label it TOP
Then mark a waypoint at the TRUNK of the tree and label it TRUNK
When you fish a pile especially with a crankbait it's best to fish it from the trunk towards the TOP because the limbs are facing towards the TOP and this helps decrease the chances of getting hung up. BUT aside from treble hook baits this will give you a visual on your GPS mapping exactly where you are at all times in relation to which way the tree lies so that you can fish whatever segment you want to fish and from whatever direction you want to fish it (which can be very important).
Now how you fish it is up totally up to you. You can fish it vertically or by casting to it. I would suggest you start off by casting to it first before going vertical. If you see fish on SI and your casting at them gets you no where vertical "MIGHT" be a better option, but not always. It depends on how deep your fish/cover is?
When I approach a pile. I usually throw a underspin type bait or a heavy swimbait to pick off any suspenders. I usually catch the biggest fish by fishing for the fish suspended above the piles or often times they will shoot up out of the pile to hit my bait and it usually happens on the first few casts. If no luck then I will go deeper with the same baits and brush the structure with my bait. If I wish to fish it slower and more methodical I will fish a jig or a finesse type bait. If I fish it vertical I'm either jigging a spoon or a dropshot.
The beauty of this feature is you can make 3 waypoints on the same screen (less than 30 seconds including screen capture) and not have to make 3 different passes for 3 different waypoints. Do keep in mind that you can mark structure as far away as 360ft on either side of the boat and not have to go directly over said fish and structure. Then go back and label them based on the order that you took them.
That my friends is why I feel SI is the ultimate fish finding technology. Not only is it a time saver in sweeping large quantities of water for fish and structure but it also allows me to see the structure/fish from a distance without having to spook them. .
Here is what my mapping looks like when I am done. I have the boat positioned to fish this submerged deep water tree from trunk to top