12/22/2017 2:47 PM | |
Posts: 439 Rating: (108) |
Hello, I manage to get GPS NMEA data from GPS shield using Node-RED and IOT 2040,here is the link to the post I made about it, but I need help to manage the data receive. I receive data like that: -GGA - Fix information The most interesting NMES GPS data is the GPRMC which looks like that: http://lakenine.com/reading-and-parsing-gps-sentences-a-linux-example/
http://www.gpsinformation.org/dale/nmea.htm#RMC
You can use online tool to get the position with the GPRMC. I successfully installed "node-red-contrib-web-worldmap 1.1.7" node and I am able to use it to display the position on a worldmap using only longitude and latitude. Enough about GPS data, I would like to convert the GPRMC string of data and convert it into something like that:
To make it short, Convert this:
Into that:
The "01131.000" must be convert "-11.31000", so java script code must consider the first 0 as a minus sign and move the dot of two position to the left. I manage to use "switch" node to extract only GPRMC data, here is a the flow. (I replace "serial" node by "inject" node for you to understand and test) Export flow:
I would like to put a "java script function" node after the "switch" node to manage the data. Best regards, Hugo |
12/22/2017 2:53 PM | ||||||||||||||||
Posts: 439 Rating: (108) |
Here is a good example of the math needs to be done: http://lakenine.com/reading-and-parsing-gps-sentences-a-linux-example/ Converting the $GPRMC Latitude and Longitude ValuesControls such as the Google Maps API want latitude and longitude values as degree values with decimal places rather than minutes, and South/West values as negatives. Here's how to convert them, using the value 4827.563 West:
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