Example: Reading an Image

The following example opens up the hdf5_test.h5 file and reads in a sample image. It is assumed that the user already knows the dataset name, either from using h5dump, or the H5G_GET_MEMBER_NAME function.

PRO ex_read_hdf5  
  
   ; Open the HDF5 file.  
   file = FILEPATH('hdf5_test.h5', $  
      SUBDIRECTORY=['examples', 'data'])  
   file_id = H5F_OPEN(file)  
  
   ; Open the image dataset within the file.  
   ; This is located within the /images group.  
   ; We could also have used H5G_OPEN to open up the group first.  
   dataset_id1 = H5D_OPEN(file_id, '/images/Eskimo')  
     
   ; Read in the actual image data.  
   image = H5D_READ(dataset_id1)  
     
   ; Open up the dataspace associated with the Eskimo image.  
   dataspace_id = H5D_GET_SPACE(dataset_id1)  
     
   ; Retrieve the dimensions so we can set the window size.  
   dimensions = H5S_GET_SIMPLE_EXTENT_DIMS(dataspace_id)  
  
   ; Now open and read the color palette associated with  
   ; this image.  
   dataset_id2 = H5D_OPEN(file_id, '/images/Eskimo_palette')  
   palette = H5D_READ(dataset_id2)  
  
   ; Close all our identifiers so we don't leak resources.  
   H5S_CLOSE, dataspace_id  
   H5D_CLOSE, dataset_id1  
   H5D_CLOSE, dataset_id2  
   H5F_CLOSE, file_id  
  
   ; Display the data.  
   DEVICE, DECOMPOSED=0  
   WINDOW, XSIZE=dimensions[0], YSIZE=dimensions[1]  
   TVLCT, palette[0,*], palette[1,*], palette[2,*]  
     
   ; Use /ORDER since the image is stored top-to-bottom.  
   TV, image, /ORDER  
  
END

IDL Online Help (March 06, 2007)