Good morning everybody and welcome to my channel, in today’s video we are going to learn how to correctly understand charts and bathymetric lines. The first thing we need to have clear is that the sea depths are like mountains, a series of peaks and downs within the mountain ranges, where fish constantly are moving to different zones.
The location of these fish depends on the water currents since they are the ones that determine where baitfish will be. You should always take into account that our main objective is to have a zenithal view, which means we have to translate three-dimensional objects into two-dimensional maps because the feed we receive is two dimensional.
In order to correctly understand bathymetric charts, we will need to comprehend that all the concentric images are all sectional drawings of the slopes and peaks of the underwater mountains. An incredible thank you to Pura Vida Fishing who has provided me with these infographics, which were previously made by them.
All of this has to be clearly understood. However, there is something that eludes us. All of these sectional drawings can lead to your understanding that the slopes are represented as vertical jumps that go down, which is something that can’t be interpreted. What I’m doing now looks like one of these downs, but we can’t be 100% sure. With this simple diagram, we can clearly see that the red and yellow drawings are practically identical, and you can’t identify which one goes up or down.
Nonetheless, if you rotate the camera’s angle, we can interpret the 2d image as a 3d one, which allows us to separate them, one of them being a mountain peak and the other one a downfall. This is a key idea which we have to understand fundamentally, which can’t be completely understood only with cartography and bathymetry.
This is a clear example that teaches us how to identify structures like cliffs, crag, hills and/or plateaus. You may think that with this illustration we can clearly understand the concept, however, we must not forget that ascending and descending mountainous formations are represented exactly the same. If there is no more information available (for example meters or colors), the bathymetry can only inform us of the vertical variations of the terrain, without telling us if they ascend or descend.
When we observe a normal chart, it is very important for us to understand the numbers, which tell us if the terrain goes up or down. A more precise way to know is the technology provided by Lowrance and Simrad, which have an option to color each zone with an appropriate color. In the map’s menu, in the chart details option (on the lower part), we can see the prominence where we can choose depth palette 1 or 2
Both can be modified and we can add colors so that they are easier to identify. Taking this into account, and knowing which colors are related to which depths, we can rapidly identify which landmarks are ascending or descending. This will allow us to completely understand the interpretation, in order to know which underwater landscapes we are observing.
I hope this video has taught you interpreting bathymetric lines, goodbye.
