Connectors and NMEA Logger for Depth and Lat / Long Data

[Skylark]

I am trying to set up a system to capture latitude, longitude and bottom depth. This is for a small harbor with shoaling issues. We would use the data to put on a mapping system to show where to dredge.

I have a Lowrance Elite 5 sonar-chartplotter. The manual says that there is an NMEA output socket which also could be used to connect a temperature gauge or speed log. I called a tech person at Lowrance and they said they did not have connectors and that there was no NMEA output. Should I believe them and just get another sonar-chartplotter?

Assuming it is possible to use the Elite 5, where can I find a connector for the Elite 5 to connect to a laptop? Should I be looking for a usb connector or serial connector on the laptop side? Is it a direct connection or is there some circuitry between the sonar-chartplotter and the laptop?

What program can I use to log the NMEA output?

I have OpenCPN working with charts on the laptop but have not used a gps connector. The laptop is running Windows.

I am not averse to trying to wire up a connector, if I could figure out a way to make it a reliable and solid connection.

I would use the NMEA textfile output to import into a spreadsheet, delete the unwanted columns and name the fields in the first line, then import the resulting lat/long/depth into an ArcGIS system to display depth on a chart of the river.

[Auspicious]

I'm sorry that I can't help you with your Lowrance.

I have done some amateur depth surveying. My experience was that you end up with tons of data and applying some reasonable decimation algorithm is important. Getting the time, position, and depth correlated is interesting also. Since latency is essentially unknown for the various data feeds you can assume as "close enough" that it is the same for each channel and run your surveys slowly enough so that it is indeed close enough.

Getting it on a chart requires one of 1. serious computational geometry, 2. somebody else's software, or 3. hand plotting (usually multiple passes to generate depth curves).

It's all very doable but tedious.

You might want to read what these guys have to say: TeamSurv - Hardware NMEA Logger Introduction