Function - return array instead of single value

Hey,

I have the following problem: The function stated below has an input of "lat_deg" and "long_deg" arrays. However, the output is currenty a single value. Why is that?

Thanks for your help!

function [foldername,filename,map_name,ref_name] = evaluatemapname(lat_deg,long_deg )

    %Check if we need to add zeros in front of the expression, depending on
    %the length of the number
    if(abs(lat_deg) < 10)
        map_lat = sprintf('0%d',abs(lat_deg));
    else 
        map_lat = sprintf('%d',abs(lat_deg));
    end
    
    if(abs(long_deg) < 10)
        map_long = sprintf('00%d',abs(long_deg));
    elseif(abs(long_deg) < 100)
        map_long = sprintf('0%d',abs(long_deg));
    else
        map_long = sprintf('%d',abs(long_deg));
    end
    
    %Norht, East
    if(lat_deg >= 0 & long_deg >= 0)
        foldername = sprintf('ASTGTM2_N%sE%s',map_lat,map_long);
        filename = sprintf('ASTGTM2_N%sE%s_dem.tif',map_lat,map_long);
        map_name = sprintf('Map_N%sE%s',map_lat,map_long);
        ref_name = sprintf('R_N%sE%s',map_lat,map_long);
    end
    
    %Norht, West
    if(lat_deg >= 0 & long_deg < 0)
        foldername = sprintf('ASTGTM2_N%sW%s',map_lat,map_long);
        filename = sprintf('ASTGTM2_N%sW%s_dem.tif',map_lat,map_long);
        map_name = sprintf('Map_N%sW%s',map_lat,map_long);
        ref_name = sprintf('R_N%sW%s',map_lat,map_long);
    end
    
    %South, West
    if(lat_deg < 0 & long_deg < 0)
        foldername = sprintf('ASTGTM2_S%sW%s',map_lat,map_long);
        filename = sprintf('ASTGTM2_S%sW%s_dem.tif',map_lat,map_long);
        map_name = sprintf('Map_S%sW%s',map_lat,map_long);
        ref_name = sprintf('R_S%sW%s',map_lat,map_long);
    end
    
    %South, East
    if(lat_deg < 0 & long_deg >= 0)
        foldername = sprintf('ASTGTM2_S%sE%s',map_lat,map_long);
        filename = sprintf('ASTGTM2_S%sE%s_dem.tif',map_lat,map_long);
        map_name = sprintf('Map_S%sE%s',map_lat,map_long);
        ref_name = sprintf('R_S%sE%s',map_lat,map_long);
    end

end

[KSSV]

If lat_deg and lon_deg are arrays, it is not suggested to use inequalities >,< etc.

[Stephen23]

"However, the output is currenty a single value. Why is that?"

If you expect to be able to supply arrays as the inputs then you will need to loop over their values (either explicitly or implictly) to create separate output strings (i.e. character vectors in a cell array, or string arrays). You could use a loop, or arrayfun, or compose, etc.

Note that you should read the sprintf documentation to understand what your code is doing now, and try some simple example with arrays, e.g.:

>> sprintf('%d,',1:4)
ans = 1,2,3,4,

Reading the documentation would also help you to simplify your code, e.g. replacing this

if(abs(long_deg) < 10)
    map_long = sprintf('00%d',abs(long_deg));
elseif(abs(long_deg) < 100)
    map_long = sprintf('0%d',abs(long_deg));
else
    map_long = sprintf('%d',abs(long_deg));
end

with much simpler:

map_long = sprintf('%03d',abs(long_deg));