Mapping Toolbox

hista

Create spatial equal-area histogram

Syntax

[lat,lon,num] = hista(lats,lons) returns the center coordinates of equal-area bins and the number of observations falling in each based on the geographically distributed input data.

[lat,lon,num] = hista(lats,lons,binarea) specifies the equal-area bin size, in square kilometers. It is 100 km² by default.

[lat,lon,num] = hista(lats,lons,binarea,ellipsoid) specifies the elliptical definition of the Earth to be used with the two-element ellipsoid vector. The default ellipsoid model is a spherical Earth, which is sufficient for most applications.

[lat,lon,num] = hista(lats,lons,binarea,units) specifies the standard angle unit string. The default value is 'degrees'.

Examples

Create random data:

• lats = rand(4)
  lats =
      0.4451    0.8462    0.8381    0.8318
      0.9318    0.5252    0.0196    0.5028
      0.4660    0.2026    0.6813    0.7095
      0.4186    0.6721    0.3795    0.4289
  
  longs = rand(4)
  longs =
      0.3046    0.3028    0.3784    0.4966
      0.1897    0.5417    0.8600    0.8998
      0.1934    0.1509    0.8537    0.8216
      0.6822    0.6979    0.5936    0.6449
  

Bin the data in 50-by-50 km cells (2500 sq km):

• [lat,lon,num] = hista(lats,longs,2500);
  [lat lon num]
  ans =
      0.2574    0.3757    4.0000
      0.7070    0.3757    5.0000
     -0.1923    0.8253    1.0000
      0.2573    0.8253    2.0000
      0.7070    0.8254    4.0000
  

See Also

eqa2grn grn2eqa	Greenwich/equal-area conversion
histr	Spatial equirectangular histogram

hidem

histr