Today i've used H480 for making ortomap. I'm using H920 app for waypoints with CGO3+ in timelapse mode and manual settings locked before you switch to H920 app. For path define i use Pix4DCapture (free and working on ST16 without Play Store). Then i plan manually on Waypoints app (waypoints, height, speed), then i save this mission and import it to PC. Waypoints from H920 app are simply JSON data so i manually convert this file to KML (it takes 2-3 minutes and could be done automatic with some programming skills). Next you can load this KML file to QGIS or other software and measure real distance of all mission waypoints. You know speed so it's easy to calculate avarage duration (add 2.5 seconds for each 90 degree turn you make on grid).
This is my test mission, today i've stopped on waypoint 6.
Useful images i took is around 125 but i used only 57 (like 2 seconds interval) JPG's downsized 4x times (down to 1024px).
This is google earth view with KML waypoints loaded (1155m measured with QGIS +120m of elevation)
Here is my ortho photo from WebODM (4x downsized before run due to lack of RAM).
Pretty nice match, you can improve this in QGIS before exporting to GeoTIF.
Here is max zoom without loosing detail (remember this was 60 meters and input photos were downsized 4x times to 1024px).
You can see me, my dog and H backpack in left corner
Here is Surface model and 3D model, pretty good for 57 pictures with single pass.
For good 3D results you have to double pass area with 90 degree angle so it's basically double the flight time for 3D. Anyway result are great for me!
This results keep me going on with the workflow of using H920 waypoint app and H480 drone. I like this semi manual procedure and i'll be testing this features to get perfect workflow for safe use. If you want this fast and easy just buy H520
Please do not try this with your H480 if you don't want to crash it.