Up
Database Grids
Ordnance Survey grid references are key to the GIS work undertaken at BRERC.
The LS1 database now has the ability to project grids around geometric objects 'on-the-fly' at a range of resolutions.
| figures, multiplier | square | square |
| 0,5 | 500,000 m | 500 km |
| 0,2 | 200,000 m | 200 km |
| 0,1 | 100,000 m | 100 km |
| 2,5 | 50,000 m | 50 km |
| 2,2 | 20,000 m | 20 km |
| 2,1 | 10,000 m | 10 km |
| 4,5 | 5,000 m | 5 km |
| 4,2 | 2,000 m | 2 km |
| 4,1 | 1,000 m | 1 km |
| 6,5 | 500 m | |
| 6,2 | 200 m | |
| 6,1 | 100 m | |
| 8,5 | 50 m | |
| 8,2 | 20 m | |
| 8,1 | 10 m | |
| 10,5 | 5 m | |
| 10,2 | 2 m | |
| 10,1 | 1 m | |
This is achieved by means of a database stored function (geom2grid) which takes four parameters (geometry, figures, multiplier, whether to bbox) and delivers a table of squares (designation, geometry).
Designation has been used in a service to load 20km GML files from the OS VectorMap District distribution on DVD. It can also be used to label maps published with LS2 web services (à la Interactive Maps).
Further examples to follow.
Up