finding distance from text data for latitude/longitude and creating new column of data for distance

3 次查看（过去 30 天）
douglas
douglas 2012-4-13
Hello all,
I have a series of text files with latitude/longitude data, in seperate columns, and time in another column. I would liek to use the latitude/longitude data to make a distance vs. time plot.
formula for distance based on lat/long:
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
The syntax isnt correct above as its not matlab code, just a formula on the internet.
How would I go about defining a new column of data (distance) by having it find the difference between every point of lat and long and then run the other basic operations to find distance?
the data in the text would follow this format;
Latitude Longitude
51.8885857 -2.159813307
51.888588 -2.159810551
51.88858751 -2.159811237
51.88858772 -2.159810981
51.88858774 -2.159810887
51.88858765 -2.159811144
51.88858779 -2.159810991
51.88858747 -2.159811489
51.88858758 -2.159811597
51.88858755 -2.15981158
51.88858725 -2.159811985
51.88858732 -2.159812218
  1 个评论
douglas
douglas 2012-4-13
would a double for loop work?
say
for i = 2:length(Latitude);
for j = 1:length(Latitude);
dellat = Latitude(i)-Latitude(j);
dellong = Longitude(i)-Longitude(j);
end
end
and then relate dellat and dellong with the above formula to find an array for the value of d? I haven't gotten the chance to test it yet.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

bym
bym 2012-4-13
the diff() function will calculate the difference for you without a loop. Here is a start:
loc = [51.8885857 -2.159813307;...
51.888588 -2.159810551;...
51.88858751 -2.159811237;...
51.88858772 -2.159810981;...
51.88858774 -2.159810887;...
51.88858765 -2.159811144;...
51.88858779 -2.159810991;...
51.88858747 -2.159811489;...
51.88858758 -2.159811597;...
51.88858755 -2.15981158;...
51.88858725 -2.159811985;...
51.88858732 -2.159812218];
dloc = diff(loc);
a = sind(dloc(:,1)./2).^2 + ...
cosd(loc(1:end-1,1)).*cosd(loc(2:end,1)).*sind((dloc(:,2)./2).^2);
  2 个评论
douglas
douglas 2012-4-18
This seemed to work out for me, is there a way to add each new data point as a sum of the previous ones? like mapping out a flight and having the last data point be the added sum? my results right now give me the distance traveled per data point, so it fluctuates based on speed etc. I'd like a total distance traveled

请先登录，再进行评论。

更多回答（1 个）

Andrei Bobrov
Andrei Bobrov 2012-4-13
use function distance from Mapping Toolbox
LatLon = [51.8885857 -2.159813307
51.888588 -2.159810551
51.88858751 -2.159811237
51.88858772 -2.159810981
51.88858774 -2.159810887
51.88858765 -2.159811144
51.88858779 -2.159810991
51.88858747 -2.159811489
51.88858758 -2.159811597
51.88858755 -2.15981158
51.88858725 -2.159811985
51.88858732 -2.159812218]
s1 = size(LatLon,1)
k = nchoosek(1:s1,2)
d = deg2km(distance(LatLon(k(:,1),1),LatLon(k(:,1),2),...
LatLon(k(:,2),1),LatLon(k(:,2),2))) ;
dout = zeros(s1);
dout(tril(true(s1),-1)) = d;
dout = dout + dout';
variant without Mapping Toolbox
L = [51.8885857 -2.159813307
51.888588 -2.159810551
51.88858751 -2.159811237
51.88858772 -2.159810981
51.88858774 -2.159810887
51.88858765 -2.159811144
51.88858779 -2.159810991
51.88858747 -2.159811489
51.88858758 -2.159811597
51.88858755 -2.15981158
51.88858725 -2.159811985
51.88858732 -2.159812218];
R = 6371;
dla = abs(bsxfun(@minus,L(:,1),L(:,1)'));
dlo = abs(bsxfun(@minus,L(:,2),L(:,2)'));
lac = cosd(L);
a = sind(dla/2).^2 + lac(:,1)*lac(:,1)'.*sind(dlo/2).^2;
d = R*2*atan2(sqrt(a), sqrt(1 - a)) ;
on Douglas's comment
out1 = diag(d,1)
out2 = cumsum(out1)

类别

在 Help Center 和 File Exchange 中查找有关 Data Import and Export 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by