islatlon.m

function tf = islatlon(lat,lon)
% islatlon determines whether lat,lon is likely to represent geographical
% coordinates. 
% 
%% Citing Antarctic Mapping Tools
% This function was developed for Antarctic Mapping Tools for Matlab (AMT). If AMT is useful for you,
% please cite our paper: 
% 
% Greene, C. A., Gwyther, D. E., & Blankenship, D. D. Antarctic Mapping Tools for Matlab. 
% Computers & Geosciences. 104 (2017) pp.151-157. 
% http://dx.doi.org/10.1016/j.cageo.2016.08.003
% 
% @article{amt,
%   title={{Antarctic Mapping Tools for \textsc{Matlab}}},
%   author={Greene, Chad A and Gwyther, David E and Blankenship, Donald D},
%   journal={Computers \& Geosciences},
%   year={2017},
%   volume={104},
%   pages={151--157},
%   publisher={Elsevier}, 
%   doi={10.1016/j.cageo.2016.08.003}, 
%   url={http://www.sciencedirect.com/science/article/pii/S0098300416302163}
% }
%   
%% Syntax
% 
% tf = islatlon(lat,lon) returns true if all values in lat are numeric
% between -90 and 90 inclusive, and all values in lon are numeric between 
% -180 and 360 inclusive. 
% 
%% Example 1: A single location
% 
% islatlon(110,30)
%    = 0
% 
% because 110 is outside the bounds of latitude values. 
% 
%% Example 2: A grid
% 
% [lon,lat] = meshgrid(-180:180,90:-1:-90); 
% 
% islatlon(lat,lon)
%    = 1 
% 
% because all values in lat are between -90 and 90, and all values in lon
% are between -180 and 360.  What if it's really, really close? What if
% just one value violates these rules? 
% 
% lon(1) = -180.002; 
% 
% islatlon(lat,lon)
%    = 0
% 
%% Author Info
% This function was written by Chad A. Greene of the University of Texas at
% Austin's Institute for Geophysics (UTIG). http://www.chadagreene.com. 
% March 30, 2015. 
% 
% See also wrapTo180, wrapTo360, projfwd, and projinv.  

% Make sure there are two inputs: 
narginchk(2,2)

% Set default output: 
tf = true; 

%% If *any* inputs don't look like lat,lon, assume none of them are lat,lon. 

if ~isnumeric(lat)
    tf = false; 
    return
end

if ~isnumeric(lon)
    tf = false; 
    return
end
if any(abs(lat(:))>90)
    tf = false; 
    return
end

if any(lon(:)>360)
    tf = false; 
    return
end    

if any(lon(:)<-180)
    tf = false; 
end

end