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Improving veg management using historical aerial photography
The way producers access historical imagery in QLD has changed. In this post, AgForce QLD walks through how to access what you need for the purposes of vegetation mapping.
During the AgForward project, the use of historical aerial photography to allow producers to contest their Property Map of Assessable Vegetation (PMAV) proved invaluable in many cases.
The process to access this photography was not straightforward: request a search based on Lot on Plan numbers, book an appointment to review the photos, borrow required photos if second set available otherwise purchase photocopies of prints, produce a mapping layer and return the prints. Analysis then commenced to compare the historical photos with recent satellite imagery and current vegetation mapping. One advantage of this process was the ability to review both federal and state government owned aerial photography.
Access to Queensland historical aerial photography has now changed.
Search for your property based on options available, Lot on Plan is recommended.
Search for available historical aerial photography.
Review the year’s available then expand the year to review the list of available photos.
Place the mouse pointer over the photo title to see its footprint (coverage), for example Film QAP220 Frame 3.
Click on the View button to review the individual photo.
Once you have identified the photos required click on the Download button to access the free 400dpi JPG images for each frame.
In this example eight 1951 photos were downloaded to provide complete coverage of this property. The footprints shown for each photo are a guide only and when stitched together may result in gaps and the requirement to download additional images.
The photos downloaded are effectively dumb images as they have no reference to spatial coordinates and when imported into a mapping application will float out in space. Each image needs to be tied down to their correct location on the earth’s surface using an appropriate coordinate system. AgForce offers a mapping service to transform these individual images into a spatial layer suitable for mapping requirements. For more information about this service go to www.agforceqld.org.au.
You can now compare the 1951 photos with newer imagery like Google Earth (2013). Vegetation in some areas was thinner 62 years ago.
If QImagery does not have the year required, you could try Geoscience Australia (GA) but it will cost. Visit the Geoscience Australia website here, click on the online catalogue link (you need to know the 1:250,000 map number your property falls in), click on the right map number box and a list will appear. The oldest photography available for this property is 1963. Click on the link to open the required flight line diagram to determine the photos required for your property.
In this example three photos would be required and cost approximately $300 for the digital scans. Sight unseen may be an issue as the scale of this photography is 1:80,000 and may not show the amount of information required.
Please contact me if you have any questions using QImagery or require a quote to create a mapping layer from historical photography.