Standardization of national shift grids for the transformation between national projected reference frames and ETRS89

Transcription

1 Standardization of national shift grids for the between national projected reference frames and Lennard Huisman Kadaster Netherlands EUREF 2014 June 3-7, Vilnius, Lithuania

2 Outline Motivation Existing procedure User friendly procedure Issues Proposal 2/20

3 Motivation September 2013 June 2014: Reconnaissance to phase out stelsel van de Rijksdriehoeksmeting (RD) Many scenarios defined Main conclusions a. First step: Exchange of geo-information in (Necessary for INSPIRE-datasets anyway) b. Need for a (more) user friendly procedure between RD and a. relies on b. New version of PCTRANS software (s and other geodetic computations) in development at Hydrographic Survey Will use Open Source libraries (proj4) 3/20

4 Existing procedure: RDNAPTRANSTM (X, Y, Z) Bessel-1841 (X, Y, Z) RD-projection 4/20 Bessel-1841

5 Existing procedure: RDNAPTRANS TM (X, Y, Z) Bessel-1841 (X, Y, Z) Bessel-1841 RD Correctiongrid Overhauser Spline interpolation Pseudo-RD RD-projection 5/20

6 Existing procedure: Belgium (X, Y, Z) BD72 (X, Y, Z) BD72 LB72 Correctiongrid Bilineair interpolation LB72 Lambert72- projection 6/20

7 Existing procedure: Great Britain (µ, λ) OS TM-projection (E ETRS, N ETRS ) OSGB36 (E OSGB, N OSGB ) Correctiongrid Bilinear interpolation 7/20

8 Procedures NL, B, GB,... similar (µ, λ) Similarities Other Datum Use of a correction/shift grid to projected coordinates Not implemented in GIS 8/20

9 Procedures NL, B, GB,... similar (µ, λ) Similarities Other Datum Use of a correction/shift grid to projected coordinates Not implemented in GIS Not user friendly 9/20

10 NTv2 (National Transformation version 2) Correction to ellipsoidal coordinates Implemented in GIS (user friendly) Included in EPSG database Database with s and projections used in GIS Datum 1 (µ, λ) NTv2 shift grid Datum 2 (µ, λ ) Available for Germany (EPSG:15948) Great Britain (EPSG:5338) Switzerland (EPSG:15486)... 10/20

11 NTv2 Correction to ellipsoidal coordinates Implemented in GIS Included in EPSG database Available for Germany Great Britain Switzerland... 11/20...An accuracy of a few cm inside of each federal region is achieved by the transforamtion. Near the borders of the federal regions, the accuracy is some dm, such that overall a sub-meter accuracy is achieved... (translated from online.de/geodaetische- Grundlagen/Transformation/Transf ormation-beta2007/)

12 NTv2 Correction to ellipsoidal coordinates Implemented in GIS Included in EPSG database Available for Germany Great Britain Switzerland... 12/20...The difference in transformed coordinates between the original OSTN02 format and the NTv2 format is insignificant (0.001m on average, 0.01m maximum).... (from: business-and-government/helpand-support/navigationtechnology/os-net/ostn02-ntv2- format.html)

13 cts/chenyx06.parsysrelated downloadlist downloadfile.tmp/entzerru ngsgittergross.jpg 13/20

14 Comparison for 25 meter gridded DEM Meter Other Datum NTv2 shift grid (different from/to datum) Other Datum / (µ, λ, h) 14/20

15 Comparison for 10 second grid at h=43m Other Datum NTv2 shift grid (different from/to datum) Other Datum / (µ, λ, h) 15/20 [m]

16 Comparison for 10 second grid at h=43m Boundary problem Topography Other Datum NTv2 shift grid (different from/to datum) Other Datum / (µ, λ, h) 16/20 [m]

17 Procedures (µ, λ) Other Datum NTv2 shift grid (different from/to datum) NTv2 shift grid (same from/to datum) (µ, λ ) Other Datum / (µ, λ ) 17/20

18 Procedures (µ, λ) Other Datum Other Datum NTv2 shift grid (different from/to datum) NTv2 shift grid (same from/to datum) (µ, λ ) Other Datum / (µ, λ ) 18/20

19 Procedures (µ, λ) NOT AVAILABLE IN GIS Other Datum Other Datum 1) Most GIS cannot handle a and a shift grid at one time 2) No standard (file) format for shifts grids to projected coordinates NTv2 shift grid (same from/to datum) (µ, λ, h) NTv2 shift grid (different from/to datum) Other Datum / (µ, λ ) 19/20

20 Procedures - conclusions The remaining procedure is height dependent Height dependency caused by 1. Difference in from / to ellipsoids 2. Rotation and scale of NTv2 shift grid (different from/to datum) It is not straightforward to adopt NTv2 Other Datum / (µ, λ, h) 20/20

21 Proposal (µ, λ) How can we get our existing procedure implemented in GIS? Other Datum EPSG is the key to implement procedure in GIS Database with s and projections used in GIS Supports NTv2 Might support projection to projected coordinates if (and only if) adopted by multiple countries How to proceed? How many countries have the same issue? Contact presenters of national reports? Possibility to adopt (so not necessarily develop) a standard file format and interpolation (PCTRANS)? 21/20

22 1 µ 1B 22/20

23 1 µ 1B µ1g 23/20

24 1 2 µ 1B µ 2B µ 1G 24/20

25 1 2 µ 1B µ 2G µ 2B µ 1G µ 1B = µ 2B µ 1G µ 2G µ 1G -µ 1B µ 2G -µ 2B 25/20