A community-safety team in Brisbane is handing its public-access defibrillator register to ambulance dispatch, which loads GDA2020 / MGA zone 56 only. The register mixes GDA94 and GDA2020 coordinates, row by row, and a GDA94 row passed through unchanged puts a cabinet about a metre and a half from where it hangs.
A community-safety team in Brisbane keeps its register of public-access defibrillators (AEDs) as MGA zone 56 eastings and northings. Rows captured before the team moved to GDA2020 are in GDA94 / MGA zone 56 (EPSG:28356); later rows are in GDA2020 / MGA zone 56 (EPSG:7856). The datum field says which. Ambulance dispatch loads GDA2020 / MGA zone 56 only, and a GDA94 coordinate read as GDA2020 puts a cabinet about 1.5 m from where it hangs: the other side of a wall, or the wrong doorway.
Every position in the register was fixed by GNSS against the national CORS network. That decides the transformation: EPSG:8048, GDA94 to GDA2020 (1), the 7-parameter transformation whose scope is GDA94 coordinates derived through GNSS CORS. ArcGIS Pro 3.7 lists it as GDA_1994_To_GDA2020_1. The national conformal grid, EPSG:8446 (GDA_1994_To_GDA2020_NTv2_3_Conformal), gives equivalent results and is accepted too.
Use any GIS: ArcGIS Pro 3.7, QGIS or a script. You are graded on the file you hand in.
brisbane-aed-register: a table, no geometry. Download it as GeoJSON (every geometry is null) or as CSV, which carries the same fields and an empty geometry_wkt column at the end. In ArcGIS Pro, use the CSV: it opens as a table, which is what XY Table To Point takes as its input. The fields arrive under these names:
| field | type | meaning |
|---|---|---|
asset_id | text | The register's id for the cabinet: AED- and four digits |
site_name | text | The premises the cabinet serves |
easting | number (metres) | MGA zone 56 easting, in the datum datum names |
northing | number (metres) | MGA zone 56 northing, in the datum datum names |
datum | text | GDA94 or GDA2020: the datum the row was captured in |
| In the register | In the handover |
|---|---|
A GDA94 row | A point built in GDA94 / MGA zone 56, then transformed to GDA2020 / MGA zone 56 with EPSG:8048 (or the conformal grid, 8446) |
A GDA2020 row | A point built in GDA2020 / MGA zone 56, and not moved |
datum | Kept as captured_datum, exactly GDA94 or GDA2020 as the register had it |
asset_id, site_name | Kept as text, unchanged |
One GeoPackage holding a point layer named aed_sites, declared as EPSG:7856 (GDA2020 / MGA zone 56), with one point per register row and these fields:
| field | type |
|---|---|
asset_id | text |
site_name | text |
captured_datum | text |
The dispatch loader reads those three fields by name; any other field is ignored. Each point has to sit within 0.25 m of where its cabinet stands in GDA2020.
ArcGIS Pro writes to a file geodatabase by default, which the loader cannot read. Create the GeoPackage with Create SQLite Database (Spatial Type GeoPackage) and export the layer into it with Export Features, naming the output aed_sites.
These are where the teaching is. Read them twice.
Modelled on a register handover from a community-safety team to ambulance dispatch, with defibrillator positions © OpenStreetMap contributors (ODbL 1.0). The transformation rule is EPSG:8048 "GDA94 to GDA2020 (1)", whose scope is "Transformation of GDA94 coordinates that have been derived through GNSS CORS", and NSW Spatial Services' "Transformation methods between GDA94 and GDA2020". The workflow follows Esri's ArcGIS Pro 3.7 documentation ("XY Table To Point (Data Management Tools)", "Export Table (Conversion Tools)", "Project (Data Management Tools)", "Create SQLite Database (Data Management Tools)", "Export Features (Conversion Tools)" and "Geographic datum transformations"), the transformation names in Esri's "Projection Engine Database Documentation" for ArcGIS Pro 3.7, and Esri's ArcGIS Pro Associate 2025 exam information guide (EAPA_2025): "Identify how to control the coordinate system and geographic transformation in ArcGIS Pro" and "Apply established workflows to correct issues with projections and transformations". Modelled on Esri's documentation; Kharita is not affiliated with Esri.
Download the data from the Data tab, prepare it in the tool you use — QGIS, ArcGIS Pro, FME, GDAL or a script — and upload what came out.
Deliver as GeoPackage, layer aed_sites, in EPSG:7856.
Read shows what the file was read as; Submit grades it. The file itself is not kept — what was read from it is.
9 scored, 0 informational
Delivered as a GeoPackage layer under the agreed name
10%The layer declares GDA2020 / MGA zone 56 (EPSG:7856)
10%Every point lies in Greater Brisbane
10%The three register fields are in the layer
5%The register fields are stored as text
5%Each asset_id appears once
3%Every point carries its asset_id
2%captured_datum holds one of the register's two codes
5%Each cabinet sits where it stands, with its name and captured datum
50%
