26298version 1

Page 1 of 4

Perform and explain geodetic computations

Level / 6
Credits / 5

PurposeThis 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; explaineccentricity 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

1It 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 unitstandard8800and unit standard 8801.

2The recommended reference for this unit standard is Denys, P. H. Geodesy and GPS – Survey Methods (Dunedin: School of Surveying, Universityof Otago) available from the publisher, email or telephone 03 479 7585. As this text is frequently updated candidates are advised to check with the publisher for the latest edition available.

3For current information on datums and projectionsrefer to the LINZstandards, guidelines and fact sheets available at http://www.linz.govt.nz/geodetic/standards-publications/standards/index.aspx such as:

LINZS25000 Standard for theNew Zealand Geodetic Datum 2000;

LINZS25002 Standard for New Zealand Geodetic Datum 2000 Projections.

4For performance criterion 4.2, geodetic software programmes are available from the LINZ website at http://www.linz.govt.nz/geodetic/software-downloads/index.aspx.

5For assessment againstelement 3 zenith distancemay 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

1.1Terrestrial observations are reduced and final coordinatescomputed for a three dimensional control traverse accurate to two decimal places.

Rangeclosed bearings, averaged and closed forward and back height differences, distances reduced using reducedheights, derived final coordinates.

1.2Explanation determines why reduced heights are used to reduce measured distances to horizontal distances in relation to a three dimensional control traverse.

1.3Methods of performing a control traverse adjustment are compared in terms of geodetic application.

Rangebowditch, least squares.

Element 2

Explaineccentricity corrections andperform manualeccentricitycalculations.

Performance criteria

2.1Eccentricity corrections are explained in terms of purpose and use.

2.2The 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.

Rangeaccuracy of – distance, bearing;

two calculations– one where the included angle between the target station and the main station is less than 180 degreesand one where it is greater.

2.3The effects of eccentricity at the target are corrected on an observed direction and distance to maintain the geodetic accuracy of observations using trigonometric functions.

Rangeaccuracy 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

3.1Corrections are applied to reciprocal vertical angles to determine height differences between two points accurate to at least two decimal places.

Rangecorrections – curvature and refraction, target heights, instrument heights, reciprocalvertical angle observations.

3.2Reciprocal and one way vertical angle observations are explained in terms of their comparative advantages.

Element 4

Explain and perform coordinate transformations.

Performance criteria

4.1Transformations are explained in terms of differences between GPS coordinates and datum and projections used in New Zealand.

Rangedifferences between– geodetic datum, ellipsoid, and projection;grid coordinates and geodetic coordinates.

4.2Grid coordinates (N,E) are transformed to geodetic coordinates (,λ)and vice versa within specified parametersusing a geodetic software programme.

Rangeany two local projections;

excludes manual calculations.

4.3Reductions are applied to a GPS baseline to transform the topocentric baseline vector to the equivalentprojection bearing and distance.

Rangedistance 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 you wish to suggest changes to the content of this unit standard.

 New Zealand Qualifications Authority 2019