Black cut outs on final map

Aloha Zane,

There are black cuts on my most recent map 2642-25, May 15, 2025.. I read over the job data and it said the map was patched as there was not enough overlap on the photos. My overlap was set for 79/81 which should be fine! The area is just a grassy hill with no trees. I made sure to include roads and houses in the map as well. It was just over 3G so I had to use a few extra points to submit it. I have never had an issue like this with any other maps!

Thanks.

Rebecca

BigIslandSurvey

Rebecca -BigIslandSurvey 15. Mai 2025 20:09

Offizieller Kommentar

According to your Overlap Report it shows that area is likely higher up and got less overlap which is why it fell apart and had to be filled in. Use of Terrain Awareness would have prevented this and kept the overlap even.

Another issue is that this data was taken right at solar noon for this area and is very low latitude so you had a lot of sunspot in the images. You can see how the sunspot moved with each image and changed the content. This can cause big issues in processing. If you MUST map at this time learn to use a circular polarizing filter to cut the back reflection down a bit. You are not starved for light there.

Zane 15. Mai 2025 20:19

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4 Kommentare

Thanks Zane.

I chose not to use terrain awareness, as I didn't want to fly that high in this particular area (197'). I don't have a polarizing filter, but I do have an ND filter in 16, 64, and 256. I could try the 16. I did try to use an ND filter before using the Mavic Air 2, but it was too dark and would not even take off, or wasn't able to get oriented properly. It was a while ago, so not sure exactly what happened, I just know the filter did not work! In that instance, I removed the filter, was able to fly, and the map came out fine. It was probably much brighter at this job above though....

Aloha,

Rebecca

BigIslandSurvey

Rebecca -BigIslandSurvey 16. Mai 2025 01:03 0 Stimmen

ND filters do nothing to change the structure of the image. They just knock everything down uniformly. The polarizer will reject directly reflected light specifically which knocks down only the strong sun spots.

Cameras can almost always use a short enough exposure time to overcome bright situations. There isn't really much of a reason to use ND filters for mapping.

Zane 16. Mai 2025 01:20 0 Stimmen

Thank you Zane! I will look into a polarizer. The ND was more for artistic purposes, since the F stop is fixed on my drone. I didn't intend to use it for mapping. I had it though, so thought it would be worth a try....

Thank you for the reply.

Rebecca

Rebecca -BigIslandSurvey 16. Mai 2025 02:15 0 Stimmen