I have two elevation models that I subtract from each other, to find out how the topography changed over time. For the elevation models I have given the RMSE error of the horizontal and vertical uncertainty/error.
I want to calculate the error of the resulting elevation model, that represents the differences between the two models.
I know that I have to calculate a error propagation, but I am very unsure how to do it. The method does not need to be very exact or complex, I need a simple method to state that the resulting elevation model has an error of round about xy.
The first model has a resolution of 0.05 m with an error of 0.03 m horizontally and 0.05 m vertically. The second model has a resolution of 1.0 m and an error of 0.15 m horizontally and 0.10 m vertically.
So I would say, I have four variables:
- Variable 1: 0.05 m +/- 0.03 m
- Variable 2: 0.05 m +/- 0.05 m
- Variable 3: 1.00 m +/- 0.15 m
- Variable 4: 1.00 m +/- 0.10 m
Is this correct?
How can I further calculate the error?
EDIT: I am not sure about the output variable but I think I would have two output variables.
Variable 1: output resulting from Variable 1 and Variable 3. Maybe something like XX m +/- XX m or a percentage value.
Variable 2: output resulting from Variable 2 and Variable 4