NCALM-UH/CODEM

Add propagated error to the registration.txt output

chambbj opened this issue · 2 comments

Current registration.txt output ends with

RMSEs:
X = +/-0.488,
Y = +/-0.805,
Z = +/-0.861,
3D = +/-1.276

If we assume 3m spherical error of the photogrammetrically derived foundation DSMs, then the total error is computed as

Total Error = SQRT(3^2 + 3D_RMSE^2)

In the case above, that equates to 3.26 m.

We had discussed potentially breaking that into horizontal and vertical components, but that can be added at a later time. (We'd either need a provider to specify their estimated horizontal and vertical error, or we could break down the spherical down based on some Gaussian assumptions.)

Maybe this is best shown as a new block, summarizing the assumptions and equations used, e.g.,

PROPAGATED ERROR
----------------
Assumed global 3D error = +/-3
3D_RMSE = +/-1.276
Total Error is computed as SQRT( global_3D_error^2 + 3D_RMSE^2 )
Total Error = +/-3.260
j9ac9k commented

Is the 3m spherical error of photogrammetrically derived DSMs a default value or is this coupled to the resolution?

The decision was made to just use a static value for now. In reality, it is obviously more complex than this. If a user knows more about a particular dataset, they can recalculate the propagated error.