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PostPosted: August 7th, 2021, 10:04 pm 
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How can I use a series of GPS dots to calculate time and distance for a trip or portion of a trip?

In 2010, I paddled a loop in the Missinabi region and recorded a track of where I was with a Spot device. I have a .kml file of that trip that displays on Google Earth as a series of dots with the time I was at each place. I also have a .xlsx file with each entry being lat./long. and time for each dot from the same trip. I've always wondered how many miles I paddled and how fast, especially the next to last day when I hit a wonderful rhythm and paddled from a campsite on Lake Missinabi to a campsite on Dog Lake about 3 miles from Missinabie Village. I can tell exactly when I started and exactly when I stopped for that day and for any other day on the trip, but I don't know how to use the lat./long. data to calculate distance.

Can I use some function in Google Earth or is their other software with which to calculate the distance traveled using either of the files?


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PostPosted: August 8th, 2021, 7:35 am 
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There are many ways of doing this. If you import it into GE,click edit and then 'show elevation profile" you can move your mouse along to show dist to any intermediate pt or to the end

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PostPosted: August 8th, 2021, 7:41 am 
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You are looking to apply the Haversine formula to calculate distance between lat/long points.
https://www.movable-type.co.uk/scripts/latlong.html

I used it to caclulate my planned route from a Google earth .kml file for the Yukon River canoe races and to predict arrival at any given waypoint using the formula in an Excel file for each of 926 waypoints over the 1000 mile race. Each waypoint gets labeled with its distance (in tenths of a mile) from the start in Whitehorse on my maps. Calculation of left turn or right turn (LT/RT) is also automatically inserted into the labels within the excel file. It all goes into my GPS route display as I paddle during the race.

Here is one segment reinserted iinto Google Earth.
Image


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PostPosted: August 8th, 2021, 8:05 am 
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There is a measuring tool on the lefthand bar at the bottom on google earth.


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PostPosted: August 8th, 2021, 8:15 am 
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Why bother with those geeky equations when it can be easily done in GE or Caltopo(once the file is converted toGPX)?

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PostPosted: August 8th, 2021, 8:47 am 
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Of course you can ue the measurement tool directly from GE if you want. I do the "geeky" thing because it is a fun and rewarding mental exercise to accomplish as I also do my detailed route map study. I can visually recognize vitually every turn point on the river as I arrive, and know what comes next. I did it so my pit crew could predict and know where I am at any time from an excel spreadsheet and predict future arrival points (including race finish time) from downloaded real time SPOT data entered into the spreadsheet.


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PostPosted: August 8th, 2021, 2:29 pm 
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wotrock wrote:
Why bother with those geeky equations when it can be easily done in GE or Caltopo(once the file is converted toGPX)?


I was thinking along these lines plus a few others last night and thought I had a fairly easy solution.....

BUT

At first I was testing my theory using a .kml file that I picked at random. It was "working" with some effort buit then I decided I would try the same plan with a .kml file I downloaded from Spot many years ago.....

That's where the problems showed up, problem number one, I tried importing the .kml file into Mapsource but that was a nogo, Mapsource could not load the Spot .kml file. Next I tired coinverting the .kml file to .gpx using an online file converter....that didn't work either!

I suspect the Spot .kml files are incompatible with anything either than Google, when I downloaded data from Spot (back in the day) I always downloaded all three options, a .kml, .gpx & .csv, the .gpx version imports into Mapsource (or Basecamp) just fine and would provide the info @fritz was looking for but it sounds like Fritz only has the .kml and .csv files.

For the times and locations, one can find those simply by opening the .kml file in Notepad, each line contains the lat/long and date/time for each waypoint. (just don't save and overwrite the original .kml)

Perhaps the easiest way to get the distances is to use Mapsource/Basecamp, recreate the waypoints and then convert them to a "route" or freehand draw a "track" for better accuracy.

Unfortunately after doing some hunting around I found no way to export a .gpx file from Google Earth, I did find a number of people trying to do this but the answer seems to be a definitive no not possible, all suggestions were to convert the file to .gpx using an online converter which I tested on a few .kml files that I created, they would convert but the Spot one would not.

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PostPosted: August 8th, 2021, 3:47 pm 
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I like to use GPSBabel to do all of my file conversions. Have had no problems converting from .kml to .gpx or to CSV for opening with Excel to perform calculation functions, then saving as CSV and converting back again to open with GE. That is how I got the miles and labels on the GE map image I posted above.


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PostPosted: August 8th, 2021, 4:22 pm 
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Yeah I just tried something similar with an old Spot .kml and got "some" usable results.

@Fritz

If you send me the .kml file I might be able to produce some results for you. The email link below is valid so send away if you like.

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PostPosted: August 8th, 2021, 7:59 pm 
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I've tried the Google Earth method without success. The show elevation profileitem under the Edit menu is greyed out despite my clicking/highlighting the name of the .kml file or any of its waypoints.

As a math curious person, I'm intrigued by the haversine method and may try it just for fun.

In the mean time, I've taken Recped up on his offer and sent him my .kml, xlxs, and .gpx files to see if he can help.

I love MYCCR for all the thoughtful help available here!


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PostPosted: August 8th, 2021, 8:41 pm 
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Fritz wrote:

As a math curious person, I'm intrigued by the haversine method and may try it just for fun.

e!


Whatever turns your crank!! :lol: I did spherical geometry as part of a surveying course----360 deg in a triangle and all that. I have 'processed' enough hairy-assed equations to dome for a while so I'll pass. Have fun!!

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PostPosted: August 9th, 2021, 6:22 am 
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wotrock wrote:
Fritz wrote:

As a math curious person, I'm intrigued by the haversine method and may try it just for fun.

e!


Whatever turns your crank!! :lol: I did spherical geometry as part of a surveying course----360 deg in a triangle and all that. I have 'processed' enough hairy-assed equations to dome for a while so I'll pass. Have fun!!

Fun facts: Spherical trigonometry is the study of curved triangles, triangles drawn on the surface of a sphere, such as approximates the surface curvature of the earth.
On a flat plane, the sum of the interior angles of any triangle is exactly 180°. On a sphere, however, the corresponding sum is always greater than 180°. The Haversine formulae take this into account. There is nothing "hairiy-assed" about simple math.
Unless you are circumnavigating the perimeter around a trianglar shaped plot during a survey, the value of 360 degrees does not enter the picture of spherical trig in a triangle.


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PostPosted: August 9th, 2021, 8:09 am 
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I still have trouble solving partial differential equations in my head------but maybe that's just me. And the faltung integral trips me up every time!!

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