Tuesday, 5 February 2019

Getting the tide function to work OpenCPN - OpenPlotter


The Tides feature of OpenCPN does not include world-wide tidal stations.  So this means depending on where you are in the world the tide function for the area you are displaying on OpenCPN will either work or it won't. If you have found you cannot see tide information when you turn on the tide function in OpenCPN here is how we did it. I will do a PC installation first then move on to our OpenPlotter.

After replacing the supplied tide and current data with new files we have tide data at our finger tips.

On a fresh install of OpenCPN you will need to replace the files in the tcdata folder.

Firstly make sure OpenCPN is not running.

PC 
For OpenCPN installed on a PC go to the folder C:\Program Files (x86)\OpenCPN\tcdata to replace the existing files. The files are names HARMONIC.IDX and HARMONIC.

I downloaded the replacement harmonic files tcdata.zip from Terry's site , the link to download the file is about 3/4 the way down the page.

I created a new folder in the tcdata folder called old harmonic and copied the old files into it. I then copied the tcdata.zip file into the tcdata folder and extracted the contents.

tcdata.zip extracted into C:\Program Files (x86)\OpenCPN\tcdata
Restart OpenCPN and see if you can see the tidal stations.


What to look for tide station local to your location.
Tide station are easier to see at lower zoom levels.
In the above screen capture when at this zoom level, at a glance  you can see the state of the tide e.g flowing or ebbing. Above we see the arrows denote the tide direction and it is just about full tide as can be seen from the next screen capture below.

Right click on the tide symbol you require information of and this window will pop up.


OpenPlotter
For OpenCPN as part of the OpenPlotter package the install is similar but will require you to type in some commands in a terminal window. more on this later.

I start by downloading the zip file from the web straight into the Downloads folder of OpenPlotter. The file tcdata.zip can be downloaded from Terry's site you will find the file about 7/8 of the way down the page.


As can be seen the tcdata file is toward the bottom of the page.

The file is down loaded to the Downloads folder as seen here.

The file is extracted into the Downloads folder.
Right click on the tcdata.zip file and extract here. 
tcdata.zip file has been extracted to the Downloads folder

The files inside the extracted zip file need to be moved to the folder  /usr/share/opencpn/tcdata/ however there is a complication and you will not be able to copy the files directly to the folder using File Manager. This is so the files can be protected and to move the files into this folder requires the use of the sudo command in a terminal window. This allows the operator to assume the identity of the administrator (root) to move files around the system.

First up you need to open a terminal window.

Click on the raspberry symbol on the top left of the screen and select Terminal from the Accessories menu
A terminal window will open up. .

After the tcdata has been extracted to the folder in Downloads I  use the following commands, for more information look at the screen capture of the terminal window to see all the commands necessary to do the job.



The Commands and session used in the terminal window are listed below. 
The commands used to move over the newly downloaded files.


cd /usr/share/opencpn/tcdata will move you to the folder where the tcdata files are stored 

ls command lists the contents of a folder, in this example of the  /usr/share/opencpn/tcdata and as can be seen the answer is the two files HARMONIC and HARMONIC.IDX

sudo mkdir oldtcdata this command makes a folder called oldtcdata

sudo mv HARMONIC HARMONIC.IDX oldtcdata will move the two files HARMONIC HARMONIC.IDX to the folder called oldtcdata.

cd command changes directory (folder) in this instance cd /home/pi/Downloads/tcdata moves to the /home/pi/Downloads/tcdata folder.

ls command lists the contents of the folder in this example the reply is the two files HARMONIC and HARMONIC.IDX

sudo mv HARMONIC HARMONIC.IDX  /usr/share/opencpn/tcdata moves the two new files to the folder /usr/share/opencpn/tcdata  to be used by OpenCPN.

ls  /usr/share/opencpn/tcdata command lists the contents of the folder  /usr/share/opencpn/tcdata  and as can be seen the two files HARMONIC, HARMONIC.IDX and the folder oldtcdata.

So if these files are there then you should be ready to go, start up OpenCPN and see if you can see an tidal stations in your area.