我想从经纬度边界定义的用户指定的(非矩形)域中的每个网格单元提取数据。我的输入文件位于曲线网格上。我已经尝试过各种方法python,cdo,ncks,但我仍然无法弄清楚。我只想为输入ncfile的多边形域子集中的每个网格单元输入时间序列信息。我NCFILE信息输入在这里给出:从域ncfile提取数据
$ ncdump -h 1979_sfc_out.nc
netcdf \1979_sfc_out {
dimensions:
x = 83 ;
y = 94 ;
time = UNLIMITED ; // (8736 currently)
nv4 = 4 ;
variables:
float time(time) ;
time:axis = "T" ;
time:long_name = "time" ;
time:standard_name = "time" ;
time:units = "hours since 1979-1-2 00:00:00" ;
time:calendar = "standard" ;
float x(x) ;
x:axis = "x" ;
x:long_name = "X-coordinate in Cartesian system" ;
x:standard_name = "projection_x_coordinate" ;
x:units = "meters" ;
float y(y) ;
y:axis = "y" ;
y:long_name = "Y-coordinate in Cartesian system" ;
y:standard_name = "projection_y_coordinate" ;
y:units = "meters" ;
float lon(y, x) ;
lon:units = "degrees_east" ;
lon:valid_range = -180., 180. ;
lon:standard_name = "longitude" ;
lon:bounds = "lon_bnds" ;
float lat(y, x) ;
lat:units = "degrees_north" ;
lat:valid_range = -90., 90. ;
lat:standard_name = "latitude" ;
lat:bounds = "lat_bnds" ;
float lon_bnds(y, x, nv4) ;
lon_bnds:units = "degreesE" ;
float lat_bnds(y, x, nv4) ;
lat_bnds:units = "degreesN" ;
char mapping ;
mapping:false_easting = 0. ;
mapping:false_northing = 0. ;
mapping:grid_mapping_name = "polar_stereographic" ;
mapping:latitude_of_projection_origin = 90. ;
mapping:standard_parallel = 64. ;
mapping:straight_vertical_longitude_from_pole = -152. ;
mapping:semi_major_axis = 6370000. ;
mapping:semi_minor_axis = 6370000. ;
float SEAICE(time, y, x) ;
SEAICE:_FillValue = -9999.f ;
SEAICE:units = "fraction" ;
SEAICE:long_name = "Ice concentration (ice=1;no ice=0)" ;
SEAICE:grid_mapping = "mapping" ;
SEAICE:coordinates = "lon lat" ;
一些我已经尝试的事情是
lat1=71.2
lat2=72.9
lon1=-176.5
lon2=-160
cdo sellonlatbox,lon1,lon2,lat1,lat2 $ifile $box1_ofile
cdo sellonlatbox (Abort): Float parameter >lon1< contains invalid character at position 1!
我认为这个问题是我的输入文件具有X,Y尺寸以米为单位(不有一个负号,可能是'位置1的无效字符'),并且我要求cdo以度为单位提取纬度/经度尺寸。我有我的nc文件中的变量'映射',这可能有助于将米转换为纬度/经度,但我无法弄清楚如何去做。
而且ncks在我这里不起作用,可能是由于相同的电表< - > lon/lat问题,我用cdo看到。
ncks -v SEAICE,U10,V10 -d latitude,71.2,72.9 -d longitude,-176.5,-160. $ifile -O $box1_ofile
ncks: ERROR dimension latitude is not in input file
虽然我想提取的多边形,这些例子我曾尝试都只是矩形子集,我认为得到多边形我可以做多个矩形子集来实现我的最终多边形形状,但如果有更好的方式做到这一点,任何意见表示赞赏。
由于