Category: GIS updates

We eventually have published our long-term work, looking at environmental influences on cognitive health (longitudinal study) in the journal Environment International. 

Neighbourhood environments and cognitive health in the longitudinal Personality and Total Health (PATH) through life study: A 12-year follow-up of older Australians

Our work with Health Research Institute of University of Canberra involved designing an interactive Sankey diagram. We chose the Highcharts JavaScript library.

Below Sankey chart shows residential moves registered in a U.S. state within neighbourhoods assigned with a socioeconomic disadvantage index
(Ref. see Neighbourhood Atlas). This Area deprivation index is mapped on U.S census blockgroup level. The lines in the grapph below represent moves between classes of deprivation scores, from one area (on left) to another (on right).

We used AU nation-wide 2021 GNaf address points (n 15,150,683), and 2021 meshblock polygons (n 368,255) – attributing each point with a meshblock attribute. Runtime: 104 seconds

Steps:

Create spatial tables, e.g. with 
SELECT STV_ShpCreateTable ( USING PARAMETERS file = '/data_au/MB_2021_AUST_GDA94.shp') OVER() AS spatial_data;

copy data:
COPY data_au.mb_2021_aust_gda94 WITH SOURCE STV_ShpSource(file='/data_au/MB_2021_AUST_GDA94.shp', SRID=4283) PARSER STV_ShpParser(); EXCEPTIONS 'data1/vertica_data/exceptions_ralf'; commit;

We can pull the points file (with x/y coordinates):
copy data_au.aus_gnaf_aug21 from '/data_au/aus_gnaf_aug21_prem_2021.csv' PARSER fcsvparser(header=true);
and add geometry:
alter table data_au.aus_gnaf_aug21 add column geom geometry;
UPDATE data_au.aus_gnaf_aug21 SET geom = STV_GeometryPoint(lon, lat, 4283); commit;

Create spatial index for the polygon data; set ram-memory to 10 gig
(default 256 mb); we use the mb_code created as integer column:
SELECT STV_Create_Index(mb_code_int, geom USING PARAMETERS index='mb_index', overwrite=true, max_mem_mb = 10000) OVER() FROM data_au.mb_2021_aust_gda94;

Perform point in polygon selection: (point id has to be unique & integer):
SELECT STV_Intersect(id, geom USING PARAMETERS index='mb_index') OVER (PARTITION BEST) AS (point_id, polygon_gid) FROM data_au.aus_gnaf_aug21

We can re-run and join using gnaf_pid to get point_ids with mb_codes, this time we also account for invalid point data (where-clause):
Select aa.gnaf_pid, polygon_gid as mb_code_int from data_au.aus_gnaf_aug21 aa
join (
SELECT STV_Intersect(id, geom USING PARAMETERS index='mb_index') OVER (PARTITION BEST) AS (point_id, polygon_gid) FROM data_au.aus_gnaf_aug21
where not (geom is null or id is null)) bb
on aa.id=bb.point_id 

Results:

After a few years of data compiling, and analysis – a further paper is now published supporting urban planning – for integrating a 20min neighbourhood strategy. It ensures that people have the aility to meet most of their daily needs within a 20-minute walk/non-motorised trip from their home. It is already part of the planning policies of some city councils. 
See the article in the Int. Journal of Behavioral Nutrition and Physical Activity of the project lead by Deakin University (IPAN).

Maps: Melbourne and Adelaide