TOOLS - GSD calculator Follow Click HERE to download the tool in Excel format.Click HERE to download the tool in Open Office format. Was this article helpful? 65 out of 75 found this helpful Related articles Ground sampling distance (GSD) How to compute the Site Calibration for GCPs in an Arbitrary Coordinate System Processing thermal images Example projects Advanced knowledge - Scientific papers Article feedback (for troubleshooting, post here) 13 comments Centro Nacional de Prevención de Desastres April 23, 2019 18:12 We have a phantom 4 and I entered that parameters as show in the picture, then we fly the drone and when we entered the flight height the app Pix4DCapture says GSD 5.5, so, the question is Why it does not say 0.77? Holden (Pix4D) April 23, 2019 19:43 Hi there. The camera database has the focal length of the Phantom 4 as 3.61, not 20. can you input the correct focal length to see what value is produced? Centro Nacional de Prevención de Desastres April 24, 2019 14:30 Ohh very thanks, now the value GSD is 4.27 It's ok? Holden (Pix4D) April 24, 2019 19:43 The sensor width is also incorrect. The database has it as 6.3175. Where did you get these values from? Centro Nacional de Prevención de Desastres April 25, 2019 16:10 I asked a DJI advisor, I also saw it in the following table: According to the specifications on the official DJI page the sensor is 1 / 2.3" Holden (Pix4D) April 25, 2019 16:21 I dont see the P4 on the list. Do you have any documentation that shows that size? Edited by Holden (Pix4D) April 25, 2019 16:22 Centro Nacional de Prevención de Desastres April 25, 2019 18:14 I do not have a document of that information because the advice was an online chat of DJI support but if necessary I ask for it again by mail to justify the parameter Spiros Arethas April 26, 2019 10:14 Found it: https://support.pix4d.com/hc/en-us/community/posts/255588446-Phantom-4-Pro-Camera Holden (Pix4D) April 30, 2019 20:49 Those refer to the Phantom 4 Pro. The above is in relation to the Phantom 4 which has a different sensor. Centro Nacional de Prevención de Desastres May 01, 2019 23:19 I have that: and I have that: Holden (Pix4D) May 03, 2019 16:57 One of my smart colleagues had the answer. Thanks, Andrew!"The 20 mm focal length that DJI reports in the camera's specifications is the 35 mm equivalent focal length. The camera's actual focal length is significantly smaller than 20 mm because the camera's sensor is smaller than a standard 35 mm sensor" Jason Kennedy October 05, 2019 23:31 There is one very, very important variable missing in this equation for calculating GSD: PIXEL PITCH. Without pixel pitch, you get a much lower (higher res) GSD. Therefore, this calc does not give a true GSD. Holden (Pix4D) October 09, 2019 15:53 Hi Jason. The pixel pitch is estimated by dividing the sensor size in mm by the number of pixels in each dimension. Both are passed to the calculator. Edited by Holden (Pix4D) October 09, 2019 15:54 Please sign in to leave a comment.