The intention of the roadmaps document is to show a visual layout of the coding space for further allocations of scripts in ISO/IEC 10646 (also in the Unicode Standard). These roadmap layouts are snapshots of scripts and characters that are known as of 2003-10-17 (pre-WG2 meeting no. 44, Mountain View, CA, USA, 2003-10-20/23). This document is intended to be used as general guideline and does not attempt to make detailed allocations of characters.

Table 1 outlines the different planes of ISO/IEC 10646 and their generic contents.

Table 1: Allocations for Planes in ISO 10646
Range of UCS-4 values (Hex)	Plane #	Name of Plane
00000000 ... 0000FFFF	Plane 0	Basic Multilingual Plane - BMP; Encoded in 10646-1: 2000 and its amendments.
00010000 ... 0001FFFF	Plane 1	Supplementary Multilingual Plane for scripts and symbols (SMP), encoded in 10646-2: 2001 and its amendments.
00020000 ... 0002FFFF	Plane 2	Supplementary Ideographic Plane (SIP) encoded in 10646-2: 2001 and its amendments.
00030000 ... 0003FFFF to 000D0000 ... 000DFFFF	Plane 3 to Plane 13	Reserved for Future Allocations
000E0000 ... 000EFFFF	Plane 14	Supplementary Special-purpose Plane (SSP) encoded in 10646-2: 2001.
000F0000 ... 000FFFFF	Plane 15	Reserved for Private Use
00100000 ... 0010FFFF	Plane 16	Reserved for Private Use

The roadmap layouts are maintained by an adhoc group on Roadmaps. This group's latest working document is located at Roadmaps to Unicode. Snapshots from these layouts are submitted for WG2 acceptance for the continued work on ISO/IEC 10646 and is closely coordinated with the work on the Unicode Standard in liaison with the Unicode Consortium.

The latest snapshot of the roadmaps that has been accepted at the last WG2 meeting for the BMP, SMP, SIP and SSP can be found at:

Please note that this roadmap consolidates into a single document information for each of the planes 0, 1, 2 and 14.

• The BMP or Plane 0 roadmap locates all script and individual character additions published in the 2nd edition of ISO/IEC 10646-1: 2000 (and Unicode 3.0), in Amendment 1 to 10646-1: 2000 (included in Unicode 3.2), those accepted for inclusion in FDAM-2 to 10646-1: 2000 (included in Unicode 4.0), plus all script additions currently foreseen to be reasonable candidates for future encoding in the BMP (see snapshot bmp-4-5, 2003-09-20).
• The SMP or Plane 1 roadmap locates all script and individual character additions included in ISO/IEC 10646-2: 2001 (included in Unicode 3.1), those accepted for inclusion in FDAM-1 to 10646-2: 2001 (included in Unciode 4.0), plus all script additions currently foreseen to be reasonable candidates for future encoding in the SMP (see snapshot smp-4-2, 2003-09-11. By current estimates all remaining general scripts and symbol sets not encoded or as possible candidates for the BMP should fit within the SMP.
• The SIP or Plane 2 roadmap locates all script and individual character additions included in ISO/IEC 10646-2: 2001 (included in Unicode 3.1), those accepted for inclusion in FDAM-1 to 10646-2: 2001 (included in Unciode 4.0), plus all script additions currently foreseen to be reasonable candidates for future encoding in the SIP (see snapshot sip-4-1, 2003-05-16). This plane is envisioned as containing future Unified Ideographic character additions. The largest current Unified Ideographic character collection should fit within the BMP and SIP, as long as duplicate character encoding is avoided.

The above roadmaps indicate that these three planes should suffice for all future encoding of characters having world-wide utility. In addition,

• The SSP or Plane 14 roadmap locates all script and individual character additions included in ISO/IEC 10646-2 (and included in Unicode 3.1), those accepted for inclusion in FDAM-1 to 10646-2: 2001 (included in Unciode 4.0), plus all script additions currently foreseen to be reasonable candidates for future encoding in the SSP (see snapshot ssp-4-1, 2003-07-15). This plane is used for encoding special characters such as alphabet used for language tagging, and variation selectors.

Note that additional 10 supplementary planes are available for encoding (with an additional 2 planes reserved for private use). Should Plane 2, the SIP (Supplementary Ideographic Plane) prove insufficient for future Han character encoding, it is anticipated that further allocations may be provided on Plane 3.