Choosing a sonar data border.

When using the Benthomap sonar tool, drawing or uploading an appropriate border for the models is important. This is because the sonar tool uses a mathematical method called interpolation to estimate parameters in a location based on observations of those parameters in another location. This is how a collection of data points becomes a depth or vegetation map that fills a border.

While interpolation may seem like magic, it does require an appropriate dataset and border. Without these elements, the models will simply estimate based on what they do have, which may not be correct.

How far can your border be from the closest data? It's best to decide based on the accuracy needs of your project and how you want to balance observation and estimation. Below are some examples of using several border distances with the same dataset.

20 meters: Border is 10 meters from closest data

30 meters: Border is 15 meters from closest data

40 meters: Border is 20 meters from the closest data

The Benthomap sonar tool makes it easy to experiment with different borders. Simply return to the data input tab, delete the polygon, draw a new one, and run the tool again.