Key Facts

Aerial photography is a mapping method that captures the earth's surface from above, via drones, satellites or aircraft. Aerial photography captures the ground from the air on a known date, with each photo tied to map coordinates, so distances and areas can be measured on screen. MetroMap captures vertical (nadir) imagery looking straight down, and oblique imagery tilted about 45° to show the sides of buildings.

TL;DR

• Vertical imagery is the base for measuring, with the main MetroMap layer captured looking straight down so the scale stays even across the whole frame.
• Oblique imagery shows building facades and access points, with MetroMap Obliques tilted to capture the sides of a building as well as the roof.
• Planes suit whole cities while drones suit single sites, as the Civil Aviation Safety Authority’s (CASA) rules cap a drone's flying height and keep it within the pilot's sight.
• Each MetroMap capture is carefully planned to minimise the impact of cloud cover, rain and bushfire smoke on a clear view of the ground.
• Each capture shows a site as it was on its capture date. MetroMap displays that date on every image layer, and any later site changes appear once the next capture is flown.

Capture Methods Compared

The Verdict

Planes capture imagery across entire cities according to planned schedules, drones capture individual sites on demand, and free satellite imagery provides nationwide coverage at 10 to 60 m GSD per pixel. For councils, trades and planners, the appropriate method depends on the area requiring coverage and the level of detail needed. MetroMap’s repeated plane captures enable teams to measure roofs and land parcels across a city remotely from the office.

What are the main types of aerial photography?

The main types of aerial photography are vertical (nadir) and oblique, and the camera angle sets them apart. A vertical image points straight down and reads like a map, while an oblique image is tilted, about 45° for MetroMap Obliques, so it shows walls as well as roofs. Some captures also record near infrared light.

Vertical imagery is the base for measuring, because its straight-down view keeps the scale steady from one edge of the image to the other. That is why the main MetroMap layer is vertical.

MetroMap imagery is 7 to 10 cm of ground area per pixel. This is referred to as Ground Sample Distance, or GSD. For example, at 7 cm GSD, one pixel in the image will equal a 7x7 cm area on the ground.

Oblique imagery adds what a roof or a tree hides, and MetroMap Obliques are captured from the north, south, east and west, each at about 45°.

MetroMap Obliques show what a straight-down view misses: building facades, access points and details hidden beneath tall buildings and trees. That makes them useful for assessing building materials and the condition of a site, and for five common jobs: site planning and feasibility, property and asset inspections, condition and access checks, change monitoring, and stakeholder communication and approvals.

MetroMap oblique imagery covers select areas in Adelaide, Sydney, Melbourne, Brisbane, Perth, Canberra, Darwin and Tasmania. Capture dates for oblique imagery vary by area, and may be older than vertical imagery captures.

Some MetroMap imagery is also available in a colour infrared view. Colour infrared (CIR) uses 4-band imagery, which adds a near-infrared band to the standard colour (RGB) bands. Your eyes can't see near infrared, so the colour infrared view displays it as red. Healthy plants reflect a lot of near infrared, which is why they show up bright red, while dry or diseased vegetation appears pale green or grey.

That makes colour infrared useful for checking vegetation and crop health, managing fire risk and bushfire recovery, and monitoring soil composition.

How is aerial photography captured?

Aerial imagery is captured using planes, drones or satellites, with each method covering a different geographic area. MetroMap imagery is captured by Aerometrex planes, as well as its partners and subcontractors. Planes follow predetermined flight paths across a city, with cameras capturing images at set intervals to ensure each frame overlaps with the preceding one.

A city-wide imagery capture involves four stages:

• Flight lines are planned. Flight planners establish flight paths across the area and select dates with clear weather conditions.
• The camera captures images in sequence. Each frame overlaps with the next, enabling the images to be combined seamlessly.
• Each frame is aligned with the map. This process, known as orthorectification, aligns each image with real-world map coordinates.
• The frames are combined into a single image. The resulting orthomosaic appears as one continuous photograph, although it consists of thousands of frames. The Aerometrex team carefully checks each capture for errors as part of its quality control process.

The scale of imagery collection is substantial. In FY2026, more than 2.2 million individual frames were captured for MetroMap.

The choice of imagery capture method depends on the area being surveyed. Planes capture imagery across entire cities according to scheduled flights, while drones capture individual sites whenever a pilot conducts a flight. In contrast, free satellite imagery covers the entire country but at a significantly lower resolution.

Digital Earth Australia's guide puts each Landsat satellite pixel at 30 x 30 m of ground, and each Sentinel-2 pixel covers 10 x 10 m to 60 x 60 m, depending on the band. In contrast, MetroMap imagery captures between 7-10 cm GSD. Drone imagery can provide very high resolution imagery as it is closest to the ground.

What are the limits and disadvantages of aerial photography?

Aerial photography is limited by weather, flight rules, the trade-off between detail and coverage, and the age and accuracy of each photo. MetroMap's flight planners schedule each flight to limit the effect of cloud, rain and bushfires, and every image records a site as it was on its capture date.

Each limitation arises from specific factors:

• Weather: Every MetroMap capture is carefully planned to minimise interference from cloud cover, rain and other atmospheric conditions, including bushfire smoke.
• Flight regulations: Drones operate under stricter flight restrictions. According to CASA's drone safety rules, drones must not exceed 120 m above ground level, must remain within the pilot's visual line of sight and must maintain a minimum distance of 30 m from other people. These restrictions limit the area a drone can cover in a single flight.
• Detail versus coverage: Image detail depends on ground sample distance (GSD), which represents the ground area covered by each pixel. Achieving a finer GSD generally requires flying at lower altitudes, reducing the area captured per frame and increasing the number of flights required. The achievable GSD also depends on factors such as air traffic control altitude restrictions and camera sensor specifications. Each capture maintains a consistent GSD across the surveyed area.
• Imagery age: To maintain current coverage, MetroMap generally captures capital cities 4-6 times annually and regional areas approximately once a year, with capture dates displayed on every image layer. Each image represents a site at a specific point in time, meaning new construction remains unrecorded until the next capture.
• Positional accuracy: Image detail and positional accuracy are distinct measures. Positional accuracy describes how closely a point in an image corresponds to its actual ground position. MetroMap imagery has a positional accuracy of 3 pixels Root Mean Square Error (RMSE), a standard measure used to quantify positional errors.

Why is aerial photography important?

Aerial photography provides a dated visual record of a location, making it possible to assess site conditions and track changes over time. MetroMap maintains imagery archives spanning 25 years or more in some areas, enabling councils, trades and planners to examine sites and their historical changes without conducting site visits.

Australia's national aerial photography archive extends considerably further into the past. Geoscience Australia's collection contains "over 1.2 million aerial photos, some dating back as far as 1928". These historical records provide valuable evidence of changes in land conditions and use over time.

The National Library of Australia also maintains a collection of Australian aerial photographs captured between 1928 and 1987. State governments maintain separate archives, including Victoria's land agency, which provides public sector access to imagery ranging from historical photographs dating to the 1930s through to recent high-resolution captures.

The MetroMap archive incorporates some of these historical imagery layers within the platform, including photographs of Sydney dating as far back as 1943.

Different professional teams use MetroMap imagery for a range of applications:

• Councils assess assets, plan works and monitor changes across entire areas.
• Trades measure roofs and driveways to prepare quotes before visiting a site.
• Planners and engineers examine sites and surrounding areas before commencing design.
• GIS teams compare imagery of the same location from two dates to identify changes over time.

The MetroMap Swipe tool displays imagery from two capture dates side by side, making changes over time easier to identify, including newly constructed sheds, cleared land parcels and tree loss.

MetroMap offers this imagery through an annual subscription to MetroMap 2D aerial imagery. The MetroMap Pro plan costs $2,640 per year, including GST, for one named user, based on annual payment. The Team plan costs $6,999 per year, including GST, for up to five named users, based on annual payment. Enterprise plans are also available, with pricing provided upon request from MetroMap. MetroMap is 100% Australian operated.

What is the future of aerial photography?

The future of aerial photography lies in software that analyses imagery beyond conventional visual inspection, a capability already demonstrated by MetroMap Insights. The platform identifies and extracts six features from MetroMap imagery: buildings, pools, solar panels, trees, driveways and grass.

MetroMap Insights can identify swimming pools across a suburb, while its solar feature generates a CSV file containing addresses and other details of solar installations. Businesses can use these datasets to identify prospective customers for services such as cleaning and fencing.