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annotate main/netcdf/inst/ncread.m @ 12711:a4de85b2e6a0 octave-forge
fix bug 47014 and make test code work in matlab
| author | abarth93 |
|---|---|
| date | Fri, 19 Feb 2016 13:45:14 +0000 |
| parents | f2cf7070ccb5 |
| children |
| rev | line source |
|---|---|
| 11907 | 1 ## Copyright (C) 2013 Alexander Barth |
| 2 ## | |
| 3 ## This program is free software; you can redistribute it and/or modify | |
| 4 ## it under the terms of the GNU General Public License as published by | |
| 5 ## the Free Software Foundation; either version 2 of the License, or | |
| 6 ## (at your option) any later version. | |
| 7 ## | |
| 8 ## This program is distributed in the hope that it will be useful, | |
| 9 ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 11 ## GNU General Public License for more details. | |
| 12 ## | |
| 13 ## You should have received a copy of the GNU General Public License | |
| 14 ## along with this program; If not, see <http://www.gnu.org/licenses/>. | |
| 15 | |
| 16 ## -*- texinfo -*- | |
| 17 ## @deftypefn {Function File} {@var{x} =} ncread (@var{filename}, @var{varname}) | |
| 18 ## @deftypefnx {Function File} {@var{x} =} ncread (@var{filename}, @var{varname},@var{start},@var{count},@var{stride}) | |
| 19 ## | |
| 20 ## Read the variable @var{varname} from the NetCDF file @var{filename}. | |
| 21 ## | |
| 22 ## If @var{start},@var{count} and @var{stride} are present, a subset of the | |
| 23 ## variable is loaded. The parameter @var{start} contains the starting indices | |
| 24 ## (1-based), @var{count} is the number of elements and @var{stride} the | |
| 25 ## increment between two successive elements. These parameters are vectors whose | |
| 26 ## length is equal to the number of dimension of the variable. Elements of | |
| 27 ## @var{count} might be Inf which means that as many values as possible are | |
| 28 ## loaded. | |
| 29 ## | |
| 30 ## If the variable has the _FillValue attribute, then the corresponding values | |
|
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8476336c120c
ncread: do not replace _FillValue by NaNs for characters
abarth93
parents:
11907
diff
changeset
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31 ## are replaced by NaN (except for characters). NetCDF attributes scale_factor |
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8476336c120c
ncread: do not replace _FillValue by NaNs for characters
abarth93
parents:
11907
diff
changeset
|
32 ## (default 1) and add_offset (default 0) are use the transform the variable |
|
8476336c120c
ncread: do not replace _FillValue by NaNs for characters
abarth93
parents:
11907
diff
changeset
|
33 ## during the loading: |
| 11907 | 34 ## |
| 35 ## x = scale_factor * x_in_file + add_offset | |
| 36 ## | |
| 37 ## The output data type matches the NetCDF datatype, except when the attributes | |
| 38 ## _FillValue, add_offset or scale_factor are defined in which case the output | |
| 39 ## is a array in double precision. | |
| 40 ## | |
| 12635 | 41 ## Note that values equal to the attribute missing_value are not replaced by |
| 42 ## NaN (for compatibility). | |
| 43 ## | |
| 11907 | 44 ## @seealso{ncwrite,ncinfo,ncdisp} |
| 45 ## | |
| 46 ## @end deftypefn | |
| 47 | |
| 48 function x = ncread(filename,varname,start,count,stride) | |
| 49 | |
| 50 ncid = netcdf_open(filename,'NC_NOWRITE'); | |
| 51 [gid,varid] = ncvarid(ncid,varname); | |
| 52 [varname_,xtype,dimids,natts] = netcdf_inqVar(gid,varid); | |
| 53 | |
| 54 % number of dimenions | |
| 55 nd = length(dimids); | |
| 56 | |
| 57 sz = zeros(1,nd); | |
| 58 for i=1:length(dimids) | |
| 59 [dimname, sz(i)] = netcdf_inqDim(gid,dimids(i)); | |
| 60 end | |
| 61 | |
| 62 if nargin < 3 | |
| 63 start = ones(1,nd); | |
| 64 end | |
| 65 | |
| 66 if nargin < 4 | |
| 67 count = inf*ones(1,nd); | |
| 68 end | |
| 69 | |
| 70 if nargin < 5 | |
| 71 stride = ones(1,nd); | |
| 72 end | |
| 73 | |
| 74 % replace inf in count | |
| 75 i = count == inf; | |
| 76 count(i) = (sz(i)-start(i))./stride(i) + 1; | |
| 77 | |
| 78 x = netcdf_getVar(gid,varid,start-1,count,stride); | |
| 79 | |
| 80 % apply attributes | |
| 81 | |
| 82 factor = []; | |
| 83 offset = []; | |
| 84 fv = []; | |
| 85 | |
| 86 for i = 0:natts-1 | |
| 87 attname = netcdf_inqAttName(gid,varid,i); | |
| 88 | |
| 89 if strcmp(attname,'scale_factor') | |
| 90 factor = netcdf_getAtt(gid,varid,'scale_factor'); | |
| 91 elseif strcmp(attname,'add_offset') | |
| 92 offset = netcdf_getAtt(gid,varid,'add_offset'); | |
| 93 elseif strcmp(attname,'_FillValue') | |
| 94 fv = netcdf_getAtt(gid,varid,'_FillValue'); | |
| 95 end | |
| 96 end | |
| 97 | |
| 12711 | 98 netcdf_close(ncid); |
| 99 | |
| 100 # the scaling does not make sense of characters | |
| 101 if xtype == netcdf_getConstant('char') || ... | |
| 102 xtype == netcdf_getConstant('string') | |
| 103 | |
| 104 return; | |
| 105 end | |
| 106 | |
| 107 if !isempty(fv) || !isempty(factor) || !isempty(offset) | |
| 11907 | 108 if !isa(x,'double') |
| 109 x = double(x); | |
| 110 end | |
| 111 end | |
| 112 | |
| 12711 | 113 if !isempty(fv) |
| 11907 | 114 x(x == fv) = NaN; |
| 115 end | |
| 116 | |
| 117 if !isempty(factor) | |
| 118 x = x * factor; | |
| 119 end | |
| 120 | |
| 121 if !isempty(offset) | |
| 122 x = x + offset; | |
| 123 end | |
| 124 |