GIS Question: How do I use Course Data?

mpapet · 05-19-2016, 11:43 PM

DIY programmer back again with another question. I'm working with .gpx formatted files. Here's a sample line:

Code:

<trkpt lat="34.59250545" lon="-120.1390539"><ele>107.0</ele><course>238.5</course><speed>0.18973666</speed><hdop>0.6</hdop><src>gps</src><sat>22</sat><time>2015-03-14T14:26:11Z</time></trkpt>

Course = 238.5

http://www.topografix.com/gpx_manual.asp#course

I have a basic understanding of postGIS at this point and can find points and calculate distance just fine. I don't understand the use/use case of Course.

michaelk · 05-20-2016, 07:09 AM

Course is the current true heading path in degrees i.e 0-359.9. Cardinal headings are 0 degrees being north, 90 degrees east, 180 degrees south and 270 degrees west. So 238.5 degrees means you are traveling southwest.

https://en.wikipedia.org/wiki/Course_%28navigation%29

sundialsvcs · 05-23-2016, 07:10 AM

. . . and, in some cases, courses are expressed in local magnetic bearings for the convenience of short-term navigators.

What is a "course?" "First star to the right, and straight on 'til morning!"

alberich · 05-23-2016, 08:40 AM

Course data is obviously exsessively amassed statistical data. Meaning the device notes not only the trackpoint at intervall, but with it also in what direction the device is headed. For exampla if you walked forward, backwards, or sideways (isn't that useful?). I'm not sure maybe it is also the vector of movement. That would not be much more than a redundancy to the track itself at that point.

And of course timestamp, calculated speed and sea level.

When I use GPS tracks for orientation I need simply the chain of lat/lon coordinates. I don't mind elevation, but I am not even sure what the benefit is.

Everything else is statistical overhead as long as i am only concerned with orientation on a specific geopraphical path. All it does is slowing down file processing in my smartphone and taking up space.