# Build DEM and ortho from DSLR images taken from helicopter **URL:** \ **Category:** PIX4Dmapper\ **Created:** [March 1, 2022, 7:26pm UTC](https://community.pix4d.com/t/build-dem-and-ortho-from-dslr-images-taken-from-helicopter/21657 "2022-03-01T19:26:15Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![bbennett](https://avatars.discourse-cdn.com/v4/letter/b/c0e974/32.png) [@bbennett](https://community.pix4d.com/u/bbennett)\ **Post date:** [March 1, 2022, 7:26pm UTC](https://community.pix4d.com/t/build-dem-and-ortho-from-dslr-images-taken-from-helicopter/21657/1 "2022-03-01T19:26:15Z")
Hi, I’m wondering if it is feasible to take photos from a helicopter with a DSLR (Nikon D750) and build a proper orthomosaic and DEM from them? Would Pix4D be able to use the orientation of the camera and GPS (if I add a GPS dongle to the Nikon D750)? Cheers, Julian ---
**Author:** ![Mike\_K](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/mike_k/32/4697_2.png) [@Mike\_K](https://community.pix4d.com/u/Mike_K)\ **Post date:** [March 1, 2022, 8:13pm UTC](https://community.pix4d.com/t/build-dem-and-ortho-from-dslr-images-taken-from-helicopter/21657/2 "2022-03-01T20:13:59Z")
Hi Julian, Yes, this is very doable. PIX4Dmapper is camera agnostic so it can processing imagery from your Nikon or any DSLR for that matter. As for the GPS dongle, if it writes the data directly to the image exif then there is nothing more you need to do. However, often you may have a CSV file that contains the GPS and orientation data. If this is the case then you can import the file along with the images and Mapper will read the corresponding data. It is a very straightforward process. I think the most difficult parameter to maintain will be your image overlap since I assume you will be triggering the camera manually. ---
**Author:** ![bbennett](https://avatars.discourse-cdn.com/v4/letter/b/c0e974/32.png) [@bbennett](https://community.pix4d.com/u/bbennett)\ **Post date:** [March 1, 2022, 10:47pm UTC](https://community.pix4d.com/t/build-dem-and-ortho-from-dslr-images-taken-from-helicopter/21657/3 "2022-03-01T22:47:30Z")
Excellent, thanks Mike. It’s good to know that this could work in principle. I agree that getting proper overlap will be challenging, especially shooting out of a moving helicopter. Would you have any advice for data collection? How would you do it? ---
**Author:** ![Mike\_K](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/mike_k/32/4697_2.png) [@Mike\_K](https://community.pix4d.com/u/Mike_K)\ **Post date:** [March 1, 2022, 11:11pm UTC](https://community.pix4d.com/t/build-dem-and-ortho-from-dslr-images-taken-from-helicopter/21657/4 "2022-03-01T23:11:26Z")
Interesting problem. My initial thoughts are to compare this flight to a manual flight with a drone. I know of several cases where users flew a drone manually but set the shutter to capture images at regular intervals. Essentially every 2-3 seconds an image was captured. If the drone was flown steady then the overlap could be somewhat maintained. So, if you know your camera parameters, flight height, and flight speed then you should be able to calculate how often the shutter needs to be triggered. It is a bit of a complex math problem but I think you have enough of the variables to make your calculations. The article below can help you perform some of the calculations. > **[TOOLS - GSD calculator](https://support.pix4d.com/hc/en-us/articles/202560249-TOOLS-GSD-calculator)** > > Calculate the Ground Sampling Distance (GSD)  and the image footprint on the ground by inputting values for the: > > Sensor width (Sw), > Focal length (Fr), > Flight height (H), > Image width (imW), > Image h...