Good morning All. Does anyone have any book recommendation for learning about Aerial Photogrammetry? I'm looking for something modern that references drones but I'm sure the main principals are the same so any recommendations will do.
Gregg
Not a recommendation but a source, see: https://my.asprs.org/ASPRSMember/Shop/ASPRSMember/Store/StoreLayouts/Store_Home.aspx?hkey=4a812fec-2a42-47ba-a740-e83ff28c3ea2
Haven't kept up with the field (now that there are multiple sensor systems field now known as Remote Sensing) . A good free resource is here: http://www.mat.uc.pt/~gil/downloads/IntroPhoto.pdf
Not a photogrammetrist but once was a Carto Tech (Photo) many, many years ago.
Aerial Photogrammetry
Don't know the aspects of photogrammetry you'd like to learn. However, for starters, there are two books that address the technical issues.
THE BASICS
Elements of Photogrammetry by Paul R Wolf - McGraw-Hill Inc 1974
A COMPREHENSIVE REFERENCE
Manual of Photogrammetry, Fourth, Fifth or Sixth Edition
American Society of Photogrammetry
https://www.asprs.org/press-releases/manual-of-photogrammetry-sixth-edition-now-available.html
Elements of Photogrammetry by Paul R Wolf is the classic text, I am guessing it has been updated, mine is the 1974 edition, BUT the science hasn't changed, just the tools have been updated.
SHG
Thanks for the relpies. I'm interested because I just picked up a quadcopter and I'm going to play around with aerial photography. I'm not sure how far I'll go with it but I am interested in creating some ortho mosaics and surfaces so i want to know the correct procedures for planning fights (photo overlap, flight height, ground control, QA/QC, ect). This is all just a learning experience at this point.
Gregg
There is a significant difference between the requirements for traditional photogrammetry and UAV work. With low level flying, variations in camera orientations can easily leave gaps in the coverage (or at least not give sufficient overlaps to enable some points to appear on sufficient photographs.
Typically overlaps of around 85% forward and 75% transverse are what you should be attempting to achieve, much higher than the 60%,10% traditionally looked for. You need also to consider that ground objects may well have heights which are a substantial percentage of the flying height, so they will hide adjacent detail - another reason for aiming at heavy coverage. If you get detail to appear on 9 or more photos then all should be well; 4 or less will certainly leave areas unresolved.
Ground control density depends on what accuracies you are after and the platform/camera combination you are using.For accuracies equivalent to ground survey you will be looking for control at around 150-200m spacing throughout the site, flying at 350-400 ft. For a simple orthophoto 4 corner points and using the on-board GPS may give you enough hold.
Assuming you have appropriate software, that should carry out the flight planning semi-automatically, but be aware that direction changes at the end of lines should always be made into the wind - otherwise you can find yourself well downwind of where you want to be. I'm assuming you have already read up on the legal requirements for flying and when it becomes commercial use.
Getting the photographs is the easy bit. Having the survey knowledge to control them and to understand when the "answer" is wrong is the skillful bit. A lot of it comes down to experience and that takes time.
Digital is cheap (vs film), even with our full size digital mapping cameras we often do considerable more overlap than traditionally, 80% is pretty common. Granted there are some different considerations with UAS due to small format cameras, closeness to objects, less stable platform, etc. If you aren't familiar with traditional photogrammetric map production you leaning curve will be steeper.
SHG