AT_3D

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Overview

AT_3D is a class specially designed to handle Aerial Triangulation (AT) computation of a three-dimensional block, sometimes called Independent Model Block Adjustment.  The mathematic models used in the adjustment is three dimensional conformal  transformation (7 parameters).  All parameters are determined simultaneously by least squares technique.  The mathematic model is non-linear, however, no approximate values of parameters are required from users.

A user can control the number of iterations by setting the maximum number at which the computation terminates.  However, computation may stop before reaching the maximum number of iterations, if a preset required accuracy is achieved. 

In practice, it is not common that  a block adjustment can achieve a good result at the first run, due to human error and large amount of data.  There will be always some editing in data files, and it can be done very easy in Noobeed, by putting a slash sign, "/", in front of a record to turn them into a comment record.  Individual standard deviation can be always put at the end of an observation at will, though a default value is given when omitted.  The results from an adjustment are neat and easy to understand. 

Member data

Name Data type Meaning
focal double focal length of photo (this will help estimate initial values of parameters)
no_iterate int no of maximum iteration
sd_gcp double standard deviation of ground control coordinate
sd_xmymzm double standard deviation of model coordinate

 

Operator

no operator provided

 

Construction function

{AT_3D} ret  =  AT_3D()

Example:

->block_2 = AT_3D()

 

Lfunction

object.FOCAL()       =  {double} left-value

object.NO_ITERATE()  =  {int} left-value

object.SD_GCP()      =  {double} left-value

object.SD_XMYMZM()   =  {double} left-value

Example:

->block_2.sd_gcp() = 0.50

->block_2.sd_xpyp() = 0.030

 

Class function

 ADJUST FOCAL  LOADGCP LOADOBS NO_ITERATE
SD_GCP SD_XMYMZM      

 


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