FOSS4G UK 2018 talk on different visualisations examples using school and pupil datasets. with open source software including PostgreSQL, PostGIS, QGIS, pgRouting.

1. Visualising
school
catchment
areas
Ross McDonald
@mixedbredie
& Roger Garbett
@reagarbett
Angus Council

2. Sec. catchment areas

3. Sec. catchment areas + Schools

4. Sec. catchment areas + Schools + Pupils

5. All catchment areas

6. All catchment areas + Schools

7. All catchment areas + Schools + Pupils

8. #cartofail

9. Jackson Pollock – Convergence (1952)

10. School Name In Catchment On roll
Arbroath Academy 723 640
Arbroath 790 858
Brechin 490 470
Carnoustie 720 732
Forfar Academy 1264 971
Monifieth 600 898
Montrose Academy 781 810
Webster’s 584 665

11. Convex hulls around points

12. How similar are the hulls v catchments?
School Hausdorff Distance
Arbroath Academy 10786.11436
Carnoustie High School 12089.85805
Forfar Academy 14875.58697
Brechin High School 16173.88699
Webster's High School 17435.49058
Arbroath High School 17897.3712
Monifieth High School 19965.69684
Montrose Academy 26048.84715
Monifieth High School 26559.60197
Monifieth High School 29441.0212
Monifieth High School 32072.78722
Forfar Academy 33494.96229
Forfar Academy 34145.29587
Webster's High School 41377.54145
ST_HausdorffDistance

13. School Hausdorff Distance
Timmergreens_Primary_School 1731.781666
Inverkeilor_Primary_School 2126.061069
Auchterhouse_Primary_School 2255.042931
Strathmartine_Primary_School 2692.634275
Arbirlot_Primary_School 3031.15279
Newbigging_Primary_School 3374.436552
Colliston_Primary_School 3382.872103
Inverarity_Primary_School 3671.3657
Eassie_Primary_School 4083.874877
Mattocks_Primary_School 4838.524264
Murroes_Primary_School 4944.509153
Carmyllie_Primary_School 5366.863652
Monikie_Primary_School 5605.587575
Edzell_Primary_School 5689.958939
Newtyle_Primary_School 6718.80455
Tealing_Primary_School 7054.552578
Rosemount_Primary_School 7104.241394
Stracathro_Primary_School 7737.626576
Maisondieu_Primary_School 7864.206572
Glamis_Primary_School 7897.602526
Friockheim_Primary_School 8188.045971
Muirfield_Primary_School 8248.403932
Warddykes_Primary_School 9139.01384
Borrowfield_Primary_School 9981.867569
Northmuir_Primary_School 10772.74056
Birkhill_Primary_School 11083.09715
Airlie_Primary_School 11322.43266
Tarfside_Primary_School 12599.0575
Liff_Primary_School 12607.8253
Strathmore_Primary_School 12656.01378
Aberlemno_Primary_School 12760.94431
Woodlands_Primary_School 13369.26143
Seaview_Primary_School 14594.95696
Isla_Primary_School 14998.10042
Whitehills_Primary_School 15976.5553
Cortachy_Primary_School 17253.12438
Andover_Primary_School 17681.72081
Inverbrothock_Primary_School 18383.85489
Burnside_Primary_School 18474.65586
Tannadice_Primary_School 19066.29543
Ferryden_Primary_School 19193.80757
Hayshead_Primary_School 19762.61945
Lochside_Primary_School 20013.20366
Grange_Primary_School 20923.14925
Southmuir_Primary_School 22114.15467
Carlogie_Primary_School 23437.45404
Langlands_Primary_School 25800.66565
Southesk_Primary_School 26626.14889
Ladyloan_Primary_School 53008.81887
Lochside Primary School 20013.20366
Grange Primary School 20923.14925
Southmuir Primary School 22114.15467
Carlogie Primary School 23437.45404
Langlands Primary School 25800.66565
Southesk Primary School 26626.14889
Ladyloan Primary School 53008.81887

15. QGIS geometry generators
Straight lines between points:
make_line(
make_point("p_easting", "p_northing"),
make_point("s_easting", "s_northing")
)

16. QGIS geometry generators
Kinked line between points:
make_line(
make_point("p_easting", "p_northing"),
make_point(abs("p_easting" - "s_easting")/2 +
"p_easting", abs("p_northing" - "s_northing")/2 +
"p_northing" ),
make_point("s_easting", "s_northing"))

17. QGIS geometry generators
Smoothed line between points:
smooth(
make_line(
make_point("p_easting","p_northing"),
make_point(abs("p_easting"-"s_easting")/2+
"p_easting", abs("p_northing"-"s_northing")/2 +
"p_northing"),
make_point("s_easting","s_northing")),
iterations:=4, offset:=0.25)

18. PostGIS circularstrings
CREATE OR REPLACE VIEW public.view_curvelinks AS
SELECT foo.p_id,
foo.s_uprn,
st_setsrid(st_curvetoline(st_geomfromtext(((((((((((('CIRCULARSTRING('::text || st_x(foo.start_point)) || '
'::text) || st_y(foo.start_point)) || ','::text) || (st_x(foo.middle_point) + foo.distance * cos(foo.azimuth)))
|| ' '::text) || (st_y(foo.middle_point) + foo.distance * sin(foo.azimuth))) || ','::text) ||
st_x(foo.end_point)) || ' '::text) || st_y(foo.end_point)) || ')'::text)), 27700) AS the_geom
FROM ( SELECT pupils_2018.p_id,
pupils_2018.s_uprn,
st_makepoint(pupils_2018.p_easting::double precision, pupils_2018.p_northing::double precision) AS
start_point,
st_makepoint(pupils_2018.s_easting::double precision, pupils_2018.s_northing::double precision) AS
end_point,
st_lineinterpolatepoint(st_makeline(st_makepoint(pupils_2018.p_easting::double precision,
pupils_2018.p_northing::double precision), st_makepoint(pupils_2018.s_easting::double precision,
pupils_2018.s_northing::double precision)), 0.5::double precision) AS middle_point,
pi() / 2::double precision + st_azimuth(st_makepoint(pupils_2018.p_easting::double precision,
pupils_2018.p_northing::double precision), st_makepoint(pupils_2018.s_easting::double precision,
pupils_2018.s_northing::double precision)) AS azimuth,
0.25::double precision * st_distance(st_makepoint(pupils_2018.p_easting::double precision,
pupils_2018.p_northing::double precision), st_makepoint(pupils_2018.s_easting::double precision,
pupils_2018.s_northing::double precision)) AS distance
FROM pupils_2018) foo;
st_setsrid(st_curvetoline(st_geo
mfromtext('CIRCULARSTRING(x0 y0,
x1 y1, x2 y2))),27700)

19. PostGIS 3D circularstrings
CREATE OR REPLACE VIEW public.view_curvelinks_3d AS
SELECT foo.p_id,
foo.s_uprn,
st_setsrid(st_curvetoline(st_geomfromtext(((((((((((((((((('CIRCULARSTRING('::text ||
st_x(foo.start_point)) || ' '::text) || st_y(foo.start_point)) || ' '::text) || 0) || ','::text) ||
st_x(foo.middle_point)) || ' '::text) || st_y(foo.middle_point)) || ' '::text) || (foo.distance / 2::double
precision)) || ','::text) || st_x(foo.end_point)) || ' '::text) || st_y(foo.end_point)) || ' '::text) || 0) ||
')'::text)), 27700) AS the_geom
FROM ( SELECT pupils_2018.p_id,
pupils_2018.s_uprn,
st_makepoint(pupils_2018.p_easting::double precision, pupils_2018.p_northing::double precision) AS
start_point,
st_makepoint(pupils_2018.s_easting::double precision, pupils_2018.s_northing::double precision) AS
end_point,
st_lineinterpolatepoint(st_makeline(st_makepoint(pupils_2018.p_easting::double precision,
pupils_2018.p_northing::double precision), st_makepoint(pupils_2018.s_easting::double precision,
pupils_2018.s_northing::double precision)), 0.5::double precision) AS middle_point,
pi() / 2::double precision + st_azimuth(st_makepoint(pupils_2018.p_easting::double precision,
pupils_2018.p_northing::double precision), st_makepoint(pupils_2018.s_easting::double precision,
pupils_2018.s_northing::double precision)) AS azimuth,
0.25::double precision * st_distance(st_makepoint(pupils_2018.p_easting::double precision,
pupils_2018.p_northing::double precision), st_makepoint(pupils_2018.s_easting::double precision,
pupils_2018.s_northing::double precision)) AS distance
FROM pupils_2018) foo;
st_setsrid(st_curvetoline(st_geo
mfromtext('CIRCULARSTRING(x0 y0
z0, x1 y1 z1, x2 y2 z2))),27700)

20. Sec. catchment areas with arcs

21. Webster’s High School detail

22. 3D arcs in QGIS2ThreeJS (sec. schools)

23. 3D splines in Blender (sec. schools)

24. 3D splines in Blender (pri. schools)

28. What
about
routes to
schools?

29. The situation
• 15,885 children traveling to and from
school every day
• Some travelling more than 30 minutes
each way
• Fragmented catchment areas
• Sub-optimal distribution of children (or
was it schools?)

30. OS MasterMap Highways Network layer

31. Highways Network
• Topological link and node network
• Classifications
• One ways and no entries
• Turn, height, weight, width restrictions
• Supplied as GML
• Geometry and attributes loaded into
PostGIS with FME

32. CREATE EXTENSION pgrouting;

33. Routable network in QGIS with plugin

34. Astar shortest path from home to school

35. Batch process the whole network

36. 20 minute driving distance from school

37. ST_VoronoiPolygons (PostGIS 2.3.x +)

38. Use the database, Luke!
• 24k nodes = 24k Voronoi polygons
• QGIS ~ 4 hours
• PostGIS ~ 5 minutes
• 15,885 pupils, 57 schools
• Turn Restricted Shortest Path (with RRI)
• PostGIS ~ 2 hours

39. Identifying pupils with long journey times

40. Identifying pupils with long journey times

41. 15 – 30 minute travel time

42. 20 – 40 minute travel time

43. 10 minutes from school

44. 10 – 20 minute travel time

46. Fastest routes, shortest path

48. Fastest routes, shortest path

49. 1 hour travel

50. 1 hour to school

51. The tools
• PostgreSQL database with PostGIS and
pgRouting super powers for routing
• QGIS Time Manager for image sequences
• Avidemux for animation sequences
• FFmpeg for conversions
• QGIS2ThreeJS for interactive 3D models
• Blender for 3D visualisations

52. The results
15,885 daily journeys to school
43,700km travelled each day
1450 hours of daily travel time
200+ children with > 1hr daily travel
The results from the results
We’ll have to wait and see.

54. Grateful thanks
• QGIS PSC and devs for awesomeness
packaged
• Twitter #GISTribe and pgRouting mailing
lists
• Owen Powell and Craig Taylor for Blender
tips and inspiration
• Roger, for writing an address geocoder

55. Are we there yet?
mcdonaldr@angus.gov.uk
@mixedbredie
garbettrea@angus.gov.uk
@reagarbett
Next QGIS UK User Group (Scotland)
Oct/Nov 2018
http://qgis.uk/
All spider images CC BY-NC pngimg.com