Recently I got some gridded data to visualize on a map. However, I found that the array storing the gridded data cannot be shown normally on the map. The first column and bottom row are ignored when plotted on the map. I wrote a demo to show the problem.

;This is a test code;
data=[[1,15,48,1],[45,34,38,34],[78,1,25,13],[34,21,36,57]]

;Plot the map;
m = MAP('Geographic',limit=[0,-10,20,10])
m.mapgrid.LABEL_POSITION = 0
m.mapgrid.LINESTYLE = '-.'
m.mapgrid.GRID_LATITUDE = 5
m.mapgrid.GRID_LONGITUDE = 5
m.mapgrid.FONT_SIZE = 6
m['Latitudes'].LABEL_ANGLE = 0
m['Longitudes'].LABEL_ANGLE = 0

;Visulize the array;
im = IMAGE(data,
IMAGE_DIMENSIONS=[20,20],
IMAGE_LOCATION=[-10,0],
grid_units='degrees',
transparency=30,
rgb_table=13,
order=1,
margin=0,
POSITION=[0.1,0.1,0.75,0.75],
overplot=m)

continent = MAPCONTINENTS()

c = COLORBAR(target=im,/BORDER,orientation=1,TEXTPOS=1,position=[0.7,0.1,0.73,0.75],TITLE='data (unit)')
c.FONT_SIZE = 6

In theory, the 4*4 grids should be shown with a spatial resolution of 5 deg from lon: -10, lat: 0. However, the plotted result just showed 3*3 grids, with the first column and bottom row not shown in the plot.

Could someone help with this problem? Thanks!!