Pitt Town Precinct
I'm digitising road infrastructure assets in ArcGIS this week but the aerial photography we have access to is dated 2014 whilst the Pitt Town Precinct has undergone significant change over the last two years. Luckily Google Maps recently updated their satellite imagery so I was able to pull a few images together and overlay them in ArcGIS over our existing imagery.
It gives me a better idea where to digitise assets like road markings and line work that just isn't possible if the road hasn't been constructed in the 2014 imagery.
With 2016 imagery you can see from the screenshot below where the road sits in relation to the road centerline.
Stitching it together in ArcGIS isn't like Photoshop where you just line up the seams. Using the Georeferencing tool you have to warp the imagery and reproject it. With the different scale and resolution between the two image tiles, it's a tad difficult to line up perfectly, however accuracy isn't critical for the task I'm trying to achieve. +/- 15 metres is better than no information whatsoever!
In the above screenshot I'm georeferencing the imagery over the top of the existing 2014 aerial photography, and using the digital cadastre database (DCDB) for property boundaries. You can read about the georeferencing tool here.