How much is (in kms) 1 degree of Longitude in the Earth?

Hi all, I am quiet new to Matlab and maybe my question sounds a bit trivial. I would like to know how many km corresponds 1 degree of LONGITUDE in the Earth (average radius: 6371 km, I am using the global model IASP91). I know that 1 degree in LATITUDE is about 111 km (k = (pi/180)*earth_radius) and that the corresponding longitude is a function of latitude. In particular, I suppose that near the equator the longitude in kms is about the cosine of the latitude at the same position. I would like to know if there is a more precise relationship or an existing function in Matlab which calculates that. Thank you so much for your help,

Leonardo

Answer 1

[José-Luis]

https://se.mathworks.com/help/map/ref/deg2km.html

Or perhaps:

https://se.mathworks.com/help/map/ref/stdist.html

provided you have the mapping toolbox.

[Leonardo Colavitti]

Hi José, thanks for your answer and your timeless but I think that is not exactly what I am looking for. In fact, if I use the function deg2km and I type >> deg2km([1 1]) my answer is = 111.1949 111.1949 same values for Latitude and Longitude (is not really true). I already check the Mapping Toolbox but it is not very useful, also because in my case I don't have to compute any distance.

Cheers, Leonardo

[José-Luis]

If you're happy with assuming a WGS-ellipsoid:

https://se.mathworks.com/matlabcentral/fileexchange/5379-geodetic-distance-on-wgs84-earth-ellipsoid

I don't get it. Your question says:

"How much is (in kms) 1 degree of Longitude in the Earth?"

And then in your comment:

"I don't have to compute any distance."

What gives?

Just calculate the distance along a pair of coordinates.