Introduction
MVC（Maximum-value composite）方法计算得出多个矩阵之间对应位置的最大值，空间数据处理中比较常用，尤其是NDVI。这里介绍两个版本的IDL语言MVC函数，其区别在于计算过程的内存占用情况，若输入N个文件，第一版内存占用为N，第二版则仅有1/N，后者相比前者对内存要求较小，适用于单个文件较大的情况。
第一版
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48 | ;;Created by LI Xu
;;20 November, 2013
;;Version 1.0
;;Discrption
;;MVC, the maximum-value composite method
;;infullname: string array, consist of N files with full path
;;strSaveDir: string, the dirctory of result
;;strflag: string, flag to month or year , etc..
;+
; :Description:
; Describe the procedure.
;
; :Params:
; infullname
; strSaveDir
; strflag
;
;
;
; :Author: LiXu
;-
pro MVC, infullname, strSavepath
;;Read one by one
ok=Query_Tiff(infullname[0], info)
Cols=info.dimensions[0]
Rows=info.dimensions[1]
N_Dim=size(infullname, /n_elements)
Pics=DblArr(N_Dim, Cols, Rows)
for ii=0, N_Dim-1 do Begin
Pics[ii, *, *]=Read_Tiff(infullname[ii], GEOTIFF=GEOVAR)
endfor
;;Run >
Result=Pics[0, *, *]
;;Loop >
for jj=1, N_Dim-1 do Begin
Result=Result>Pics[jj, *, *]
endfor
;;Write a result tiff
Write_Tiff, strSavePath, Result, GEOTIFF=GEOVAR, /float
print, strSavePath+' done!'
end
|
第二版
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33 | ;; Created by LI Xu
;; Version 1.0
;; June 6, 2016
;; Description:
;; MVC Method
;; If you have any question about this code,
;; please do not hesitate to contact me via E-mail:
;; jeremy456@163.com
;; Blog:
;; http://blog.sciencenet.cn/u/lixujeremy
;; http://lixuworld.blogspot.com/
pro MVC_TinyMomory, fullnames, stroutpath
;; Create a blank Matrix
ok=Query_Tiff(fullnames[0], info)
Cols=info.dimensions[0]
Rows=info.dimensions[1]
N_Dim=size(fullnames, /n_elements)
OutMat=DblArr(Cols, Rows)
for ii=0, N_Dim-1 do Begin
image=Read_Tiff(fullnames[ii], GEOTIFF=GEOVAR)
OutMat=OutMat>image
endfor
;;Write a result tiff
Write_Tiff, stroutpath, OutMat, GEOTIFF=GEOVAR, /float
print, stroutpath+' done!'
end
|
Matlab版
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39 | % Created by LI Xu
% Version 1.0
% June 21, 2016
% Description:
% MVC Matlab Version
% If you have any question about this code,
% please do not hesitate to contact me via E-mail:
% jeremy456@163.com
% Blog:
% http://blog.sciencenet.cn/u/lixujeremy
% http://lixuworld.blogspot.com/
% Note;
% fullpathes: full file pathes in cell
% otpath: output file path
function MVC4Image(fullpathes, otpath)
% First Image
filepath=fullpathes{1};
[output, geo]=geotiffread(filepath);
info=geotiffinfo(filepath);
[row, col]=size(output);
output=output(:);
for ii=2:length(fullpathes)
filepath=fullpathes{ii};
image=imread(filepath);
image=image(:);
output=[output, image];
output=max(output, [], 2);
end
output=reshape(output, row, col);
geotiffwrite(otpath, output, geo, 'GeoKeyDirectoryTag', info.GeoTIFFTags.GeoKeyDirectoryTag);
end
|
References
No comments:
Post a Comment