From 1583a566a208d2451fb1acc8bcf16fbd8151983e Mon Sep 17 00:00:00 2001 From: Even Rouault Date: Sat, 29 Sep 2018 10:01:48 +0200 Subject: Add geographic offset transformation method. The Geographic offsets transformation adds an offset to the geographic longitude, latitude coordinates, and an offset to the ellipsoidal height. This method is normally only used when low accuracy is tolerated. It is documented as coordinate operation method code 9619 (for geographic 2D) and 9660 (for geographic 3D) in the EPSG dataset. It can also be used to implement the method Geographic2D with Height Offsets (code 9618) by noting that the input vertical component is a gravity-related height and the output vertical component is the ellispoid height (dh being the geoid undulation). It can also be used to implement the method Vertical offset (code 9616) It is used for example to transform: - from the old Greek geographic 2D CRS to the newer GGRS87 CRS - from Tokyo + JSLD69 height to WGS 84 - from Baltic 1977 height to Black Sea height It is also useful to document the implicit zero-offset transformation we do in pipelines such as +proj=pipeline +step +inv +proj=longlat +ellps=A +step +proj=longlat +ellps=B that can be explicited as +proj=pipeline +step +inv +proj=longlat +ellps=A +step +proj=geogoffset [+dlon=0 +dlat=0 +dh=0] +step +proj=longlat +ellps=B --- docs/source/references.bib | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'docs/source/references.bib') diff --git a/docs/source/references.bib b/docs/source/references.bib index bd3089ee..0fb077ec 100644 --- a/docs/source/references.bib +++ b/docs/source/references.bib @@ -82,6 +82,14 @@ Url = {http://www.calcofi.org/publications/calcofireports/v20/Vol_20_Eber___Hewitt.pdf} } +@Manual{EPSGGuidanceNumber7Part2, + Title = {Geomatics Guidance Note 7, part 2 - Coordinate Conversions & Transformations including Formulas}, + Institution = {International Association For Oil And Gas Producers}, + Year = {2018}, + + Url = {https://www.iogp.org/bookstore/product/coordinate-conversions-and-transformation-including-formulas/} +} + @Manual{Evenden2005, Title = {libproj4: A Comprehensive Library of Cartographic Projection Functions (Preliminary Draft)}, Author = {G. I. Evenden}, -- cgit v1.2.3