How to create spatial index for Aerial Photos

[JessiecarEsguerra]

Hi Guys, I need help in building a spatial index of Aerial photos and have the Image Service project on the fly. Appreciate any ideas or inputs from anyone who has knowledge about this.

Thanks in advance.

- Jessiecar

[NeilAyres]

But, how do you know where in the raster image (pixel position, row & col) these control points are located?

[JessiecarEsguerra]

The Aerial photo's filename is also included on the metadata.

Using the filename, I could identify what are the control points for each from the metadata.

[XanderBakker]

Can you attach an example of the Metadata for an aerial photo? Just to know what your possibilities will be...

[JessiecarEsguerra]

Sure Xander.

See attached screenshot containing a sample metadata for an Aerial photo. I tried attaching an excel file but I can't here.

[XanderBakker]

The corner correspond to the fiducial marks? Are these always in the same location (row, column in the digital image)?

[NeilAyres]

I very much doubt it. These are photos later scanned to get them into an image file.

The pixel coordinates will depend on the position through the scanner.

I very much doubt there will be any correlation between pictures as to the exact pixel locations of fiducial marks.

However, you do seem to have the picture centre in Lat/Long. Perhaps something could be engineered out of that.

[XanderBakker]

I have my doubts too, but with some numpy executed on corner rectangles with a certain extent, i think these marks can be identified and can be tied together with the metadata. Would be interesting to try this...

[NeilAyres]

It will be very interesting to see you try. Good luck

[XanderBakker]

Thanks Neil, I'm sure I can use all the luck I can get. Probably the scikit-image: Image processing in Python — scikit-image  could be very helpful.

[JessiecarEsguerra]

Thanks everyone for all your input and feedback.

We have actually tried a few photos and it was georeferenced on the right location though there's a slight misalignment which I think is expected since these are Historical photos.