Historical Aerial Photography Point Clusters

[View Map in ArcGIS] ##### ##### Abstract This dataset shows how photo centres are distributed on the map by grouping them into hexagon-shaped areas of fixed sizes. A photo centre is the point on the ground directly below the camera when a photograph was taken. Each hexagon contains a count of photo points inside it so using them makes it easier to see how many historical aerial photographs were taken in each area. This dataset is a photo density visualisation aid created from the [Historical Aerial Photography Flight Lines and Photo Centres] dataset It does not contain the detailed information available in the source dataset. Layers available Several map layers are provided, each showing photo point clusters at a different hexagon size: * Clusters_Level9 – Uses hexagons about 4000 sqkm across to group photo centres. * Clusters_Level8 – Uses hexagons about 6000 sqkm across to group photo centres. * Clusters_Level7 – Uses hexagons about 8000 sqkm across to group photo centres. * Clusters_Level6 – Uses hexagons about 12000 sqkm across to group photo centres. * Clusters_Level5 – Uses hexagons about 14000 sqkm across to group photo centres. * Clusters_Level4 – Uses hexagons about 16000 sqkm across to group photo centres. * Clusters_Level3 – Uses hexagons about 18000 sqkm across to group photo centres. Each layer name indicates the size of the hexagon grid used to cluster the photo centres. In the [Australian Government Historical Aerial Photo Explorer] app, these clusters are shown as circles to make the map easier to understand. Even though the data is grouped using hexagons, circles are used to visualise these clusters because they provide a cleaner, uncluttered look and make it easier to identify areas where lots of photos were taken. Each circle is placed at the centre of the hexagon it represents, and its size or colour shows how many photo centres are in that area. This way, users can easily spot areas with lots of photos without needing to look at the exact hexagon shapes. ##### Data dictionary Historical Areial Photography Point Clusters - All Aggregate sizes ──────────────┬───────────────────────────────────── Attribute Name│Description ──────────────┼───────────────────────────────────── GRID_ID │Unique Identifier for the Hexagon ──────────────┼───────────────────────────────────── COUNT │Count of Aerial Photography Centroids ──────────────┴───────────────────────────────────── ##### Currency Date modified: March 2026 Next modification date: As needed ##### Data extent Spatial extent North: -2° South: -71° East: 180° West: -180° ##### Lineage statement Product created: March 2026 Product published: March 2026 This clustered dataset was derived by counting photo centre points inside hexagon grids using ArcGIS Pro (geographic mapping software). The geoprocessing tool ‘Generate Tessellation’ was used to create a grid of equal-sized hexagons covering the extent of the photo centre points. After generating the grid, the number of photo centre points in each hexagon was calculated and attached to the hexagons. This process was repeated for different hexagon sizes to produce the layers listed in the abstract. The source data used for this process was the photo centre points from the [Historical Aerial Photography Flight Lines and Photo Centres] dataset. ##### Contact Geoscience Australia, [aerialphotography@ga.gov.au]