I am currently working with a client who has a large collection of current and old aerial photography. We are currently indexing and organising this collection. Although many users are primarily interested in the most current imagery available, there are some important uses for old imagery, and in particular being able to compare what is visible in old orthos compared to the situation in more modern orthos. I am interested in good ways to present this data so that it is easy to compare different orthos.
I have managed projects to implement 'side by side' viewers (mainly of vector data) as in the example here: http://gisviewer.hcc.govt.nz/Templates/PropQueryCompare/ .
The useful function with this is that you can pan/zoom etc to different areas and both views continue to mirror the geographic extents but with different data being looked at. I am particularly interested in how people have organised the orthos to support a viewer in this type of configuration.
What I am interested in is whether anyone has done something similar, but with the ability to change each of the windows to different orthophotos of different ages? I think that this could be a good way of presenting the historic imagery that we are currently working with.
Any suggestions/examples please? (hyperlinks to publicly available sites would be great)
Thank you for your suggestion, however I think that a side by side viewer rather than a 'swipe' function is going to suit my users needs better. I am also aware of the option of a 'time-slider ' function to move through different ages of imagery but I think that a side by side viewer would still be preferable.
I am just wanting to establish a business case for this so what I am looking for is examples to explain to management and users the concept- can you point me to any examples on the web?
I have seen http://magic.lib.uconn.edu/mash_up/aerials.html which is the kind of examples that I am seeking- however I am hoping that there are other similar examples out there (I have searched myself but the search results come up with too many irrelevant results).
I am also primarily interested in techniques for how to organise/structure or mosiac historic orthophotos to best suit this purpose- whether it viewed in Saga or other software we will need to organise this first and this stage is where we are up to with our current project.
Thanks for your suggestion.