Author Topic: Inaccurate elevation values (Z-axis values)  (Read 1031 times)


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Inaccurate elevation values (Z-axis values)
« on: September 17, 2018, 02:07:40 PM »
Hello dear Agisoft community,

Currently, I am working on a project that requires high accuracy on elevation profile values (Z-axis values). The problem is that once the map is constructed by the software, I generally observe misleading information across the height values. Although, in reality, my measurements on two different position's height values are approximately the same; I find out in the software that they are much different. i.e. (40-50 meters offset).
At first, I thought that this situation might be reasoned from the occurrence possibility of some of the faulty or deceitful aerial images in my data set, which I have gathered from different drone flights, but then I find out that it does not only happen on the same place, but also appears on different places or even different maps.
After analyzing further, I determined that the map is lifted (or raised) 10 degrees to 20 degrees from one side to another, or in other words, rather than observing a flat line (height values should not be changing much once I move the cursor on an imaginary line), I observe increasing or decreasing values, which are approximately advanced by tangent 10 to 20 degrees.
I've done a search on google, and gathered some information about the GCPs (Ground Control Points), but I could not manage to implement that. I think that my problem will be solved once I correctly place those gcps. Therefore, Can any one help me by giving an example to place those points appropriate, and construct a reliable map?