对于经过地理校正的影像,我们可以在用ENVI/IDL进行二次开发时,通过以下方式获得其基本信息和map_info信息。
直接在ENVI/IDL命令行里写:
#1.基本信息
ENVI> file='D:\F\corona\test\match_img\DS1110-1118DF025_rec_geocoding_1s_match.tif'
ENVI> envi.openraster(file)
结果:
ENVI> envi.openraster(file)
% Loaded DLM: JPEG2000.
% Loaded DLM: JPEG.
% Loaded DLM: HDF5.
ENVIRASTER <327662>
AUXILIARY_SPATIALREF = !NULL
AUXILIARY_URI = 'D:\F\corona\test\match_img\DS1110-1118DF025_rec_geocoding_1s_match.hdr'
DATA_TYPE = 'byte'
INTERLEAVE = 'bsq'
METADATA = <ObjHeapVar328404(ENVIRASTERMETADATA)>
NBANDS = 1
NCOLUMNS = 12780
NROWS = 3061
PYRAMID_EXISTS = 0
READ_ONLY = 1
SPATIALREF = <ObjHeapVar328405(ENVISTANDARDRASTERSPATIALREF)>
TIME = <ObjHeapVar328406(ENVITIME)>
URI = 'D:\F\corona\test\match_img\DS1110-1118DF025_rec_geocoding_1s_match.tif'
对以上结果进行分析,可知包含了其影像的
行列数(ncolumns=12780,nrows=3061)
数据类型(data_type=‘byte’)
存储方式(INTERLEAVE= ‘bsq’)
#2.map_info信息
ENVI> raster=envi.openraster(file)
ENVI> print,raster.SPATIALREF
结果:
ENVI> print,raster.SPATIALREF
ENVISTANDARDRASTERSPATIALREF <329053>
COORD_SYS_CODE = 0
COORD_SYS_STR = 'GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]'
PIXEL_SIZE = 0.00027777777, 0.00027777777
ROTATION = 0.00000000
TIE_POINT_MAP = 127.08200, 43.625000
TIE_POINT_PIXEL = 0.00000000, 0.00000000
分析以上信息,我们可以得知影像的
1)地理坐标系统:
COORD_SYS_STR = ‘GEOGCS[“GCS_WGS_1984”,DATUM[“D_WGS_1984”,SPHEROID[“WGS_1984”,6378137.0,298.257223563]],PRIMEM[“Greenwich”,0.0],UNIT[“Degree”,0.0174532925199433]]’
2)影像一个像素所代表经纬度
(PIXEL_SIZE = 0.00027777777, 0.00027777777)
即 pixel_size =x_size, y_size
3)影像左上角的经纬度:
( TIE_POINT_MAP = 127.08200, 43.625000)
4)当然可以通过以下方式获得这些信息:
ENVI> print,raster.SPATIALREF.pixel_size
0.00027777777 0.00027777777
ENVI> print,raster.SPATIALREF.tie_point_map
127.08200 43.625000