Miscalculation of the GUID representations example?

[kkebo]

On this page, it shows that the first part of 00112233-4455-6677-8899-AABBCCDDEEFF is represented as 33 22 11 00 in raw hex and as 1122867 (=0x00112233) in integer.

However, I think it must be 857870592 (=0x33221100). Because the second and third parts are represented as 21828 (=0x5544) and 30566 (=0x7766) in integer on the page, unlike the first part, though it explains that the first three parts are all encoded in Little-Endian.

If I'm wrong, please close this issue. Thanks.

[esilvia]

Thanks for bringing this up! You're right that I mixed up the endianness of the integer interpretation, but in the other direction. It's the integer values of the middle bytes that I messed up.

Because of LittleEndian (LE) interpretation, the following should be true:

Raw Hex         Type   Integer (LE hex)   Integer (LE base 10)
[33 22 11 00]   ui32   0x00112233         1122867
[55 44]         ui16   0x4455             17493
[77 66]         ui16   0x6677             26231

I've attached a binary GUID encoded as described in hopes that'll clarify. Note that it's not actually a txt file... I just had to give it that suffix for GitHub to allow the upload.

guid.txt

I'll update the wiki shortly.

[esilvia]

It seems that I made the same mistake in the other example. Thanks for bringing this to my attention. I'll upload sample GUIDs for both.

[esilvia]

The wiki has been updated and now also includes LAS and bin samples.

https://github.com/ASPRSorg/LAS/wiki/LAS-ProjectID-Encoding-and-Representation

@kkk669 Would you mind double-checking my examples?

[kkebo]

Thank you so much. Your changes look good to me.

• https://github.com/ASPRSorg/LAS/wiki/LAS-ProjectID-Encoding-and-Representation/_compare/2f1697ca042ad15ca630ea0637f0a6b5f3d8bf00...99685c6f189eeba42d02db1fdf23d7c9d1624fee
• https://github.com/ASPRSorg/LAS/wiki/LAS-ProjectID-Encoding-and-Representation/_compare/99685c6f189eeba42d02db1fdf23d7c9d1624fee...e10707dc4574796a94db5a11e290442365a53979
• https://github.com/ASPRSorg/LAS/wiki/LAS-ProjectID-Encoding-and-Representation/_compare/e10707dc4574796a94db5a11e290442365a53979...d4a9a05863e230849473bf7454d508e868a86913

If I had to say, the word "integers" in the following line can be a little confusing.

LAS Project ID (integers):     [1122867    ][17493][26231][136 153 170 187 204 221 238 255]

How about this?

LAS Project ID (integers):     [1122867    ][17493][26231][136 153 170 187 204 221 238 255] <-- note the first three sections are interpreted as LE

[esilvia]

Done! Sorry for the delay.