htmldump data format?

[Shelia]

When I am viewing EXIF data using the htmldump command, what is the data format being used for the output?

Please see the attached image.  I just chose a random picture and selected the GPSLatitude tag and value (seen in pink).  I'm confused by the HEX and ASCII data output.  For instance looking at the GPSLatitude value I fail to understand how the value of 45 55 46.22 (as shown within the boxed detail) relates to the values shown in the leftmost and middle columns of the htmldump output.

How does 45 55 46.22

equate to HEX:
00 00 00 2d  00 00 00 01 00 00 00 37
00 00 00 01 00 00 12 0e  00 00 00 64

or ASCII:
...-.......7
...........d

???  What am I missing?

[Phil Harvey]

The tool tip tells you the format of the data.  In this case it is rational64u[3], so there are three 64-bit unsigned rational values.  See the EXIF specification for more details.

- Phil

[StarGeek]

It also helps to look at the data using the -v (-verbose) option.  It will tell you the format as well as what was extracted. For example, here's the GPS section using -v3.

Code Select Expand

  | 4)  GPSInfo (SubDirectory) -->
  |     - Tag 0x8825 (4 bytes, int32u[1]):
  |         004e: 00 00 00 5a                                     [...Z]
  | + [GPS directory with 5 entries]
  | | 0)  GPSVersionID = 2 3 0 0
  | |     - Tag 0x0000 (4 bytes, int8u[4]):
  | |         0070: 02 03 00 00                                     [....]
  | | 1)  GPSLatitudeRef = N
  | |     - Tag 0x0001 (2 bytes, string[2]):
  | |         007c: 4e 00                                           [N.]
  | | 2)  GPSLatitude = 40 41 21.12 (40/1 41/1 528/25)
  | |     - Tag 0x0002 (24 bytes, rational64u[3]):
  | |         00a8: 00 00 00 28 00 00 00 01 00 00 00 29 00 00 00 01 [...(.......)....]
  | |         00b8: 00 00 02 10 00 00 00 19                         [........]
  | | 3)  GPSLongitudeRef = W
  | |     - Tag 0x0003 (2 bytes, string[2]):
  | |         0094: 57 00                                           [W.]
  | | 4)  GPSLongitude = 74 2 40.2 (74/1 2/1 201/5)
  | |     - Tag 0x0004 (24 bytes, rational64u[3]):
  | |         00c0: 00 00 00 4a 00 00 00 01 00 00 00 02 00 00 00 01 [...J............]
  | |         00d0: 00 00 00 c9 00 00 00 05