GridLinkPositionalAccuracy¶
NRS data dictionary (extracted; corrected after review (AI-assisted review, 2026-10-02, record); awaiting confirmation)
| Dictionary table | Type | Range | Description |
|---|---|---|---|
spd small user (spd-indexdatadictionary-2026-2.docx) |
Char(1) | 1 to 8 | Indicates the positional accuracy of the GridLink grid reference allocated to each postcode. Description of status values 1. Automatically calculated to be within the building of the matched address closest to the postcode. 2. As for status value 1, except by visual inspection of OS MasterMap® Topography Layer maps. 3. Approximate to within 50 m of true position. 4. Postcode unit mean – (mean of matched addresses with the same postcode, but not snapped to a building). 5. Postcode imputed by ONS by reference to surrounding known postcodes. 6. Postcode sector mean – mainly PO boxes. 7. Postcode terminated. The accuracy of the data is as indicated by its status value immediately prior to its termination. 8. No coordinates available. Note that grid references for PO Box postcodes are assigned to the local Royal Mail sorting/delivery office and are deemed low quality. While the Gridlink® RPC is showing as 1 (which is high quality), this is purely because the address is being matched to the local Royal Mail sorting/delivery office. |
spd large user (spd-indexdatadictionary-2026-2.docx) |
Char(1) | 1 to 8 | Indicates the positional accuracy of the GridLink grid reference allocated to each postcode. Description of status values 1. Automatically calculated to be within the building of the matched address closest to the postcode. 2. As for status value 1, except by visual inspection of OS MasterMap® Topography Layer maps. 3. Approximate to within 50 m of true position. 4. Postcode unit mean – (mean of matched addresses with the same postcode, but not snapped to a building). 5. Postcode imputed by ONS by reference to surrounding known postcodes. 6. Postcode sector mean – mainly PO boxes. 7. Postcode terminated. The accuracy of the data is as indicated by its status value immediately prior to its termination. 8. No coordinates available. Note that grid references for PO Box postcodes are assigned to the local Royal Mail sorting/delivery office and are deemed low quality. While the Gridlink® RPC is showing as 1 (which is high quality), this is purely because the address is being matched to the local Royal Mail sorting/delivery office. |
| Table | Type | Nullable | Category | In the CSV export | SQL Server type |
|---|---|---|---|---|---|
history table (postcode_simd_history, SPD) |
string | no | NRS Scottish Postcode Directory field | yes | nvarchar(200) |
Provenance in the history table (postcode_simd_history, SPD)¶
Where it comes from
| Input | Field | Condition | Reaches the row by |
|---|---|---|---|
SPD/spd_postcodeindex_cut_26_2_csv/SmallUser.csv (pinned, SHA256 fc82f1091ac1…) |
GridLinkPositionalAccuracy |
records of the small-user file | the row itself |
SPD/spd_postcodeindex_cut_26_2_csv/LargeUser.csv (pinned, SHA256 dcb060cbce01…) |
GridLinkPositionalAccuracy |
records of the large-user file | the row itself |
Scope: the row itself.
What was done to it: copied. Copied as text from the NRS Scottish Postcode Directory, unchanged; the two files are stacked. (code: simd_ingest/core/spd.py: read_index_file, union_index)
How it is checked (what each check tests; whether a build passed it is in that build's manifest.json["checks"])
spd.small_user.schema: the SPD file's header is exactly the reviewed header, in orderspd.large_user.schema: the SPD file's header is exactly the reviewed header, in orderspd.columns: the two SPD files together carry the expected columnsreadback.history.index_columns: the saved file's NRS columns equal the source, re-read