Hi GIS community,
My name is Ricky. I research iceberg calving events in the Arctic. Iceberg calving defines the sudden breaking away of ice chunks from the cliff face of glaciers that move into the ocean. I use time-lapse cameras to film the calving process as the cameras allow me to get within 300 meters of the calving action without imminent death from falling ice pieces that can be the size of an average house or 12 story office block! Right now I have a couple of thousand digital photographs from which I need to accurately map the location and size of each detaching iceberg. The issue I have is that the digital photographs have no spatial information and also contain perspective errors. I have only a handheld GPS co-ordinate for the camera that took the photos. see attached photo.@
For me - the location of the event needs to be in x, y, and z coordinates while the size of the event ideally needs to be in area (which I combine with an ordinal category of extra small (XS), S, M, and L.
I will also soon have a surface DEM for the same location of the ice cliff at which the digital photographs were recording.
I was told to initially use Adobe Photoshop to draw polygons around each individual iceberg, and then to determine the centroid pixel co-ordinates of that polygon / iceberg, and then to use the subsequent photo pixel coordinates as a means to locate the same location (iceberg event) on the surface DEM.
So my first question is this: Are digital photograph pixel coordinates of any use for identifying the same location on a DEM? Would the DEM recognize the photo pixel coordinates?
Second question linked to the above: Could I transfer my polygons made in Photoshop to the DEM as a means to find the 3D area of the iceberg so I can get a handle on the iceberg size?
Which leads to a third and fourth set of questions: Is it possible to warp one of my digital photographs onto the DEM? This would give my photo a spatial reference. I then wanted to outline the polygons onto the warped photo so that my area calculation was in 3D and devoid of perspective issues. Is that possible?
Finally - if I can warp one of the photos, how would I provide spatial information to the rest of my photo batch? Would I need to manually warp every single photo on the single DEM I will soon have? Or is there a way to warp just one image and use the meta data to link this to the rest of the photo batch? My photo batch is focused on the same section of the cliff face - so essentially the space being filmed doesn't change - it's always the same section of the cliff face in view. The camera did move about in times of strong wind so there are occasions where a little bit more of the ice cliff comes into view.
Thanks everyone - I basically want the most time efficient and robust way of giving real world coordinates to iceberg calving events from thousands of 2D photos that have no spatial information / coordinates. And I have a DEM (cm scale resolution) which I am hoping can help me with this!
Merry Christmas and any advice would be very much appreciated,