Hi,
My code runs great on small data sets, but I'm trying to use it for
larger sets and I've started getting an
''loop limit expression too large for loop variable type' error when I
reach the "for j=0, num_ids-1 do begin". Why is this happening and
how can I fix it?
THANKS!
pro fractional_water_extraction_linux
;created by J. Watts (August 2010) .
; input: 1)file with fine spatial resolution data (300 m in this
example)
; 2)grid file of coarse resolution (25 km in this example).
create using lingen().
; 3)grid file with fine resolution (create by resampling the
coarse resolution grid to the resolution of
; the input fine with fine resolution data; generates pixels
with id values with that of the coarse res. grid).
; This grid was cliped to the same spatial extent of the fine
resolution input data.
; output: a coarse resolution (25 km) file with fractional coverage
information for each pixel.
; program objective: Determine fractional coverage of a certain DN
value for all fine resolution pixels within each
; coarse resolution pixel. Output fractional value for each coarse
pixel in envi binary file.
; Open index grids and store in arrays
coarse_grid = lonarr(368,390)
fine_grid = lonarr(30595,32478)
OPENR, lun1, '/measures/MODIS_MERIS_Water_Cover_panArctic/GlobCover/
25km_EASE_grid_subset_PanArctic_unq_ID', /get_lun
READU, lun1, coarse_grid
close, lun1
free_lun, lun1
OPENR, lun2, '/measures/MODIS_MERIS_Water_Cover_panArctic/GlobCover/
25km_EASE_grid_subset_PanArctic_unq_ID_300m_subGlob', /get_lun
readu, lun2, fine_grid
close, lun2
free_lun, lun2
; Initialize input grid that will hold high resolution VI data
in_data_grid = bytarr(30594,32477, 1)
openr, lun3, '/measures/MODIS_MERIS_Water_Cover_panArctic/GlobCover/
Globcover_NEASE', /get_lun
readu, lun3, in_data_grid
close, lun3
free_lun, lun3
;determine input grid data layer
VI=in_data_grid[*,*,0]
;determine output grid
out_grid = fltarr(368,390,1)
;determine the unique id values from the grid and sort these values
by order
coarse_ids = fine_grid[UNIQ(fine_grid, SORT(fine_grid))]
;print, coarse_ids
; determine the number of returned unique coarse_ids
num_ids = n_elements(coarse_ids)
;print, num_ids
; loop through each coarse_id number
for j=0, num_ids-1 do begin ; this is where I get that
error message
id = coarse_ids[j]
;count how many fine pixels occur at coarse_ids[j]
id_index = where(fine_grid EQ id, count)
count=count
fcount=float(count)
print, count
if count EQ 0 then begin
Fclass = -9999 ; gives this value to the output pixel
endif else begin
; determine how many fine pixels of a certain class are within the
coarse pixel, and have a value equal to 210.
class=210
indexed_pixels=VI(id_index)
count_class = where(indexed_pixels EQ class,count)
count2=count
fcount2=float(count2)
; print, count2
if count EQ 0 then begin
Fclass = 0
endif else begin
;compute the fraction of pixels with VI equal to 210 out of total
count.
Fclass = (fcount2 /fcount)
;print, Fclass
endelse
endelse
; place the fractional values in an out-grid
out_grid[id] = Fclass
endfor
; write the grid containing the fractional values to a file
openw, out_lun, '/measures/MODIS_MERIS_Water_Cover_panArctic/GlobCover/
GlobCover_Fractional_Water_Maps/GlobCover_FW_C210' , /get_lun
writeu, out_lun, out_grid
close, out_lun
free_lun, out_lun
end
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