Model preparation

1. Prepare the project
   1. Open the sample data project (sample_data.qgs)
   2. Change the project properties
   3. Set the background black
   4. Set the selection colour magenta
   5. Hide all the layers
2. Make an axial map
   1. Add a Google maps physical layer (Web menu > Open Layers plugin)
   2. Create a new vector layer (shape file format)
   3. Select 'Line' type
   4. Call it 'axial_new'
   5. Set the CRS to: EPSG 27700
   6. Draw some axial lines, zooming into the Barnsbury area (defined by other layers)
3. Make unlinks
   1. Create a new vector layer (shape file format)
   2. Select 'Point' type
   3. Call it 'unlinks_new'
   4. Set the CRS to: EPSG 27700
   5. Draw some unlink objects where some axial lines intersect
4. Update axial “id” column
   1. Select the axial layer
   2. Choose the field calculator (abacus tool)
   3. Select to update the existing id column
   4. Use the expression “$id” (function in the Record group)