The manual refers to starting at 200:
// Define constants for my additional namespaces.
define("NS_FOO", 200); // This MUST be even.
define("NS_FOO_TALK", 201); // This MUST be the following odd integer.
It seems natural to put namespaces that are not used for extensions in this area because it's not between 1-199 and conflicting with namespaces for well known extensions beginning at 300.
However, Extension_default_namespaces#Extension_default_namespaces.23ID_3000.2B states that custom namespaces should be above 3000.
What's the best range for systems administrators to place custom namespaces?
I'm going to try starting at 3000 now to resolve the Invalid or Virtual Namespace -1 errors when I try to create forms with Semantic and Semantic-Forms. After changing namespaces I won't forget to run maintenance/update.php and then run rebuild and update via Special:SMWAdmin.
hrm, first time using visual editor [[Evar]!] ... tried to cut and past code from main page and it wouldn't work:
Note Note: Namespaces using numbers from 3000 and higher are meant to be used by system adminiatrators to define their custom namespaces. Thus extension developers should not use this range.
It is confusing.
| using numbers from 3000 and higher.