26298 version 1
Page 1 of 4
Perform and explain geodetic computations
Level
6
Credits
5
Purpose
This unit standard is for people who are working, or who intend to work, in
the surveying profession in a geodetic context.
People credited with this unit standard are able to: perform and explain a
manual adjustment of a three dimensional control traverse using
conventional terrestrial observations; explain eccentricity corrections and
perform manual eccentricity calculations; reduce and explain vertical angle
observations; and explain and perform coordinate transformations.
Subfield
Surveying
Domain
Geodetic Surveying
Status
Registered
Status date
12 February 2010
Date version published
12 February 2010
Planned review date
31 December 2012
Entry information
Open.
Replacement information
This unit standard replaced unit standard 11132.
Accreditation
Evaluation of documentation and visit by NZQA and
industry.
Standard setting body (SSB)
Infrastructure ITO
Accreditation and Moderation Action Plan (AMAP) reference
0101
This AMAP can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Special notes
1
It is recommended that prior to assessment against this unit standard candidates are
able to perform calculations for general surveying purposes. This may be evidenced
by achievement of credit for unit standard 8800 and unit standard 8801.
 New Zealand Qualifications Authority 2016
26298 version 1
Page 2 of 4
2
The recommended reference for this unit standard is Denys, P. H. Geodesy and
GPS – Survey Methods (Dunedin: School of Surveying, University of Otago)
available from the publisher, email surveying@otago.ac.nz or telephone 03 479
7585. As this text is frequently updated candidates are advised to check with the
publisher for the latest edition available.
3
For current information on datums and projections refer to the LINZ standards,
guidelines and fact sheets available at http://www.linz.govt.nz/geodetic/standardspublications/standards/index.aspx such as:
LINZS25000 Standard for the New Zealand Geodetic Datum 2000;
LINZS25002 Standard for New Zealand Geodetic Datum 2000 Projections.
4
For performance criterion 4.2, geodetic software programmes are available from the
LINZ website at http://www.linz.govt.nz/geodetic/software-downloads/index.aspx.
5
For assessment against element 3 zenith distance may be used in place of vertical
angle observation.
Elements and performance criteria
Element 1
Perform and explain a manual adjustment of a three dimensional control traverse using
conventional terrestrial observations.
Performance criteria
1.1
Terrestrial observations are reduced and final coordinates computed for a three
dimensional control traverse accurate to two decimal places.
Range
closed bearings, averaged and closed forward and back height
differences, distances reduced using reduced heights, derived
final coordinates.
1.2
Explanation determines why reduced heights are used to reduce measured
distances to horizontal distances in relation to a three dimensional control
traverse.
1.3
Methods of performing a control traverse adjustment are compared in terms of
geodetic application.
Range
bowditch, least squares.
Element 2
Explain eccentricity corrections and perform manual eccentricity calculations.
Performance criteria
2.1
Eccentricity corrections are explained in terms of purpose and use.
 New Zealand Qualifications Authority 2016
26298 version 1
Page 3 of 4
2.2
The effects of eccentricity at the instrument station are corrected on an
observed direction and distance to maintain overall measurement accuracy in
accordance with trigonometric formulae.
Range
2.3
accuracy of – distance, bearing;
two calculations – one where the included angle between the
target station and the main station is less than 180 degrees and
one where it is greater.
The effects of eccentricity at the target are corrected on an observed direction
and distance to maintain the geodetic accuracy of observations using
trigonometric functions.
Range
accuracy of – distance, bearing;
two calculations – one where the included angle between the
target station and the main station is less than and 180 degrees
and one where it is greater.
Element 3
Reduce and explain vertical angle observations.
Performance criteria
3.1
Corrections are applied to reciprocal vertical angles to determine height
differences between two points accurate to at least two decimal places.
Range
3.2
corrections – curvature and refraction, target heights, instrument
heights, reciprocal vertical angle observations.
Reciprocal and one way vertical angle observations are explained in terms of
their comparative advantages.
Element 4
Explain and perform coordinate transformations.
Performance criteria
4.1
Transformations are explained in terms of differences between GPS
coordinates and datum and projections used in New Zealand.
Range
4.2
differences between – geodetic datum, ellipsoid, and projection;
grid coordinates and geodetic coordinates.
Grid coordinates (N,E) are transformed to geodetic coordinates (,λ) and vice
versa within specified parameters using a geodetic software programme.
Range
any two local projections;
excludes manual calculations.
 New Zealand Qualifications Authority 2016
26298 version 1
Page 4 of 4
4.3
Reductions are applied to a GPS baseline to transform the topocentric baseline
vector to the equivalent projection bearing and distance.
Range
distance includes – correction for slope, correction to ellipsoidal
surface, line scale factor correction;
bearing includes – convergence.
Please note
Providers must be accredited by NZQA, or an inter-institutional body with delegated
authority for quality assurance, before they can report credits from assessment against
unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be accredited by NZQA before they can register
credits from assessment against unit standards.
Accredited providers and Industry Training Organisations assessing against unit standards
must engage with the moderation system that applies to those standards.
Accreditation requirements and an outline of the moderation system that applies to this
standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The
AMAP also includes useful information about special requirements for organisations
wishing to develop education and training programmes, such as minimum qualifications for
tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact Infrastructure ITO askus@infratrain.co.nz if you wish to suggest changes to
the content of this unit standard.
 New Zealand Qualifications Authority 2016