Introduction to SNAP – Part 1


Introduction to SNAP – Part 1


The NZIS Positioning Stream has developed a two-part webinar aimed at those interested in learning more about how to use LINZ’s freely-available SNAP software. SNAP is widely used in New Zealand for geodetic and engineering surveys and is currently the only software that uses New Zealand’s deformation model to rigorously calculate NZGD2000 coordinates. It uses least squares to calculate coordinates and uncertainties, enabling rigorous testing against both relative and absolute accuracy standards. It can consume all common survey data types, including GNSS, levelling and traverse data.

The first webinar will start at the beginning for those who have either not have used SNAP before, or who may need a refresher.

The second webinar will focus on some more advanced analysis techniques involving multiple data types and datums (eg NZGD2000 and NZVD2016). It will also introduce the user-definable SNAP csv format. This webinar will suit those who have attended the first webinar, or who are already using SNAP in their business and are interested in extending their knowledge of the software.

Both webinars will use practical demonstrations of the software to illustrate the concepts.

Introduction to SNAP – Part 1 (90 minutes)

  • Least squares statistics (standardised residuals, error ellipses, standard error of unit weight etc)
  • SNAP files (command, coordinate and data files)
  • Minimally constrained adjustments, determining error factors, constrained adjustments
  • Running and reviewing an adjustment
  • Adding geoid heights
  • Using SNAPPLOT for visualisation and analysis
  • Example using GNSS baseline and terrestrial data

Presenter: Dr Chris PearsonBSc (Union College) MSc (University of Alaska) PhD (Otago)

I teach and conduct research in areas of Geodesy, Crustal deformation, GPS and least square adjustments. I completed my PhD from the University of Otago, New Zealand in the area of earth deformation measurements in 1991 and then spent a year working on a post-doc at Columbia University in the area of GPS processing (Bernese) working on the first major earth deformation campaign in the South Island. In 1994 Between 1994 and 2001 I worked at the University of Otago as a research fellow measuring active deformation of the Southern Alps. During this time I played a key role in the establishment and the New Zealand Tide Gages and the Southern Alps Vertical CGPS networks and nearly all of the campaign style geodetic projects in the South Island undertaken between 1993 and 2001. I was also instrumental in making the first INSAR study of a New Zealand Earthquake. Between 2001 and 2011 I worked at the National Geodetic Survey of the US where I was responsible for development of the HTDP software. During that time I played a key role in developing a comprehensive block model of deformation in the western US a new and much improved velocity for Alaska. In 2011 I returned to the School of Surveying where I currently lecture in Surv 302, Surv 451 and Surv 399.

Date: Thursday October 12th

Time: 1:00pm to 2:30pm

Duration:1.5 Hours (2 CPD Point)

NOTE: If you have registered as an individual y our CPD points will automatically be added to your Dashboard after the event takes place. If you have booked via a group booking registration you will need to update your CPD points manually.

Registration Fee: Members:$100.00 + Gst - Non-members:$130.00 + Gst

NZIS Event Registration Form.pdf

For more information please contact Vanessa Delegat on 04 471 1774 or email:


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14 Aug 2017
  • 0.00
  • 12/10/2017 - 12/10/2017
  • 13:00 - 14:30
  • Online   Online   NZ
  • $115.00Members $149.50Regular
  • Register