<div dir="ltr"><div><div><div><div>Thanks for the very helpful feedbacks!<br><br></div>I did find another site here;<br><a href="http://www.gpsvisualizer.com/map_input?form=google">http://www.gpsvisualizer.com/map_input?form=google</a><br></div>Looks like you can more easily upload your GPS-coordinates and get the map.<br><br></div>I got many good leads from your feedbacks, thanks a lot!<br><br></div>Mats<br><div><div><div><div><div><div><br>----------<br><br>Date: 29 Apr 2017 23:54:23 -0300<br>
From: "Stefan Steiniger" <br>
To: <a href="mailto:geocoding@openstreetmap.org">geocoding@openstreetmap.org</a><br>
Subject: Re: [Geocoding] Help with student project about<br>
GPS-coordinates for windsurfers!<br>
<br>
Hi Mats,<br>
<br>
I will try to answer your questions - although they are a bit broad:<br>
<br>
1. shortest distance (in the plane) between a point (surfer) and a line<br>
geometry (the coast) - packages like geos or jts can do this using their<br>
DistanceOp function. However, you would need to convert the GPS<br>
coordinate from WGS84 into a local coordinate system (such as UTM) to do<br>
this; assuming that your coast line is already in such a system.<br>
<br>
2. this depends on your speed of movement and how abrupt you have<br>
changes in direction, which are important for you. To me 10secs sounds<br>
good. I have been looking at bus fleet data with 30sec/point and that<br>
isn't good enough from some applications. So, actually your application<br>
will define what resolution is best.<br>
<br>
3. Probably using Leaflet (<a href="http://www.leafletjs.com" rel="noreferrer" target="_blank">www.leafletjs.com</a>) and displaying the GPS<br>
points from the surfer. Leaflet has quite a bit of tutorials. However<br>
this requires to have a webserver somewhere. You could probably also use<br>
a map service, such as Mapbox.com or Carto.com to display your data. But<br>
then you need to figure out how to get your live data into the platform.<br>
<br>
so far my take,<br>
Stefan</div></div></div></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 30 April 2017 at 00:10, Mats Blakstad <span dir="ltr"><<a href="mailto:mats.gbproject@gmail.com" target="_blank">mats.gbproject@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div>Hi<br><br></div>I work on a student project in a course about
Use Design at University of Oslo. Our project is to help windsurfers; We
try make a small gadget that that they can bring (using Arduino) that
will help them (1) be alerted when they move too far from land, (2) be
able to send a SOS signal indicating their position if they need help,
(3) give them updated weather forecasts.<br><br>None of us are very
experienced with GeoCoding so hope someone here can give use some small
hints or point us in best correction;<br></div><ol><li>What seem like the most reliable way to measure a persons distance from land using a gps-coordinate?<br></li><li>How
often should we save gps-coordinates to track a windsuring trail with
good enough resolution but still keep a minimum file size of gps
coordinates for trail?</li><li>What is the most simple way that we can create an online map with trail from GPS-coordinates that we can update live?</li></ol><p>Thanks in advance for any help and feedbacks!<span class="m_207696283673169205gmail-HOEnZb"><font color="#888888"><br></font></span></p><div class="m_207696283673169205gmail-yj6qo m_207696283673169205gmail-ajU"><div id="m_207696283673169205gmail-:13u" class="m_207696283673169205gmail-ajR"><img class="m_207696283673169205gmail-ajT" src="https://ssl.gstatic.com/ui/v1/icons/mail/images/cleardot.gif">Best regards<span class="HOEnZb"><font color="#888888"><br></font></span></div><span class="HOEnZb"><font color="#888888"><div id="m_207696283673169205gmail-:13u" class="m_207696283673169205gmail-ajR">Mats<br></div></font></span></div></div>
</blockquote></div><br></div>