From Decimal degrees to meter

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08-24-2014 06:28 AM
KasperSmith_Larsen
New Contributor II

Hey Guys

I have a data set Air mass trajectories (excel file) with a lot of points given in decimal degrees. I have plotted the trajectories in Arcmap but I need to know the distance between them. They span more or less from equator to Greenland so there is the issue of different E/W distances.

Regards Kasper       

1 Solution

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BruceHarold
Esri Regular Contributor

If you do not have Desktop Advanced and the Near GP tool then provided you can deal with 0.5% error then the Haversine formula might be suitable.

Or Vincenty if you want to get fancy.

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7 Replies
DanPatterson_Retired
MVP Esteemed Contributor

I don't work with data covering such a large area, but I would suggest km...in any event you probably want the geodesic distances which have new options in 10.2.1 perhaps using the Near tool

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stefanstamenov
Occasional Contributor III
stefanstamenov
Occasional Contributor III

This must work, though I never used it

Latitude/Longitude Distance Calculator

BruceHarold
Esri Regular Contributor

If you do not have Desktop Advanced and the Near GP tool then provided you can deal with 0.5% error then the Haversine formula might be suitable.

Or Vincenty if you want to get fancy.

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KasperSmith_Larsen
New Contributor II

Thanks for your answers.

I have tried using the Haversine formula in excel but I can’t get the right distance. I have calculated the following parameter:

R = earth’s radius (mean radius = 6,371km)

Δlat = lat2− lat1

Δlong = long2− long1

a = sin²(Δlat/2) + cos(lat1)*cos(lat2)*sin²(Δlong/2)

c = 2*atan2(√a, √(1−a))

d = R*c (distance)

     

As described at http://www.ig.utexas.edu/outreach/googleearth/latlong.html

It says on the web-site that angles need to be in radians and I tried with radians calculated from both decimal degrees and degrees, minutes, seconds. 

BruceHarold
Esri Regular Contributor
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KasperSmith_Larsen
New Contributor II

Now I got the Haversine fomula to work so problem solved

Thanks to all of you for your input they really helped.