Hi, I created two missions along a river and want to upload both together to create a single map. I used the same takeoff spot for each mission and took reference images on the ground at the start and end of each mission. The reference images on the ground show a five meter elevation difference between the two missions and the image altitudes are also five meters different between the two even though both were flown at same altitude. The ground elevation reported for the takeoff spot was five meters higher at the end of the first flight than at the start of the first flight.
Will this be worked out in the map processing? Should I upload a reference image for each mission or just use one to create a single map? Will the different reported altitudes between the two flights make a difference in the final map? Wondering if I should make two separate maps to deal with it. The elevation at the start of the first flight is closest to the actual elevation.
It's a linear mission about 1.5 miles long with five flight lines along a river. About 650 photos.
Thanks
That is precisely the reason we use the Ground Reference images, GPS altitude sucks!
We are looking at the barometric altitude that is associated with each image for determining the ground reference image locations. At the time of takeoff this number is zero, always.
It sounds like you took your data just fine and the elevation differences will be handled by our system.
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Thanks for that. I processed the images and the resulting map has some errors larger than I've seen before in other maps I've processed.
The horizontal positions are shifted 20 to 50 meters from their actual locations based on comparison to the maps made easy online background image, Google maps image, and Bing maps image.
The elevations are all sloping from one side of the map to the other when in reality the terrain on each side of the mostly dry channel I'm mapping is of about equal elevation, within less than about three meters difference. The DEM has a constant slope across the map such that one side is about 60 meters lower than the other. It's a long skinny map made from five flight lines along a channel so I'm wondering if that's the reason.
The photo coverage was good with pretty much the entire area of interest in the 13+ image coverage range. Wondering if there is a way to correct it or if I tried it again what I should do differently.
Thanks
Convex polygon layouts do not work as well for processing since there are add appendages going all over the place. In general we try to keep users from doing convex shapes (shapes with interior points) because of this issue. The linear mission planning tool does allow it but it is way harder to get it to turn out well. More passes helps.
We love your work! Keep it up.
