A CMAP chart is a way to map marine environments to figure out the best fishing spots and create them as custom maps. CMAP software is compatible with your sonar and GPS units on your boat so you know where you are going to go fishing. 

You could benefit from a CMAP chart because you will be able to know what is below the water and where the most populated parts of the area are so you can have the best fishing results. This software allows you to have an accurate map of any body of water.

How it Works

A CMAP chart is pretty easy to use and there are only three steps that need to be completed before you are ready to go.


The first step is to record sonar data. You will need to use a mini-SD card to do so. This will allow you to record sonar logs of different bodies of water that include depth, bottom hardness, and vegetation of the area. 

You should record a new sonar log about once every hour when you are on the water. This will ensure that you have the most accurate information possible.


If you are using a fish-finder that runs on WiFi, your sonar recordings should automatically upload to your CMAP when the unit connects to WiFi. If your mobile plan includes unlimited data, you will be able to upload even when you are on the water.

You can also upload your data by removing the mini-SD from the fish-finder and insert it into your computer. You would then need to upload your data to CMAP based on the instructions provided by the manufacturer of your CMAP device.


When you upload your data, your CMAP device will typically download a map file for each sonar log you upload. Depending on how large the file is, this could take up to a few hours to complete. If you have uploaded several files from the same body of water, you can merge the files into one single map file.

Once you have your downloaded map files, you can save them to your mini-SD card. Then, you just have to put the mini-SD card into your fish finder when you are on the water. You will be able to catch larger fish and a higher quantity of fish with the help of CMAP.