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| author | Even Rouault <even.rouault@spatialys.com> | 2020-04-04 19:27:26 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-04-04 19:27:26 +0200 |
| commit | 0ff11909243616f4b8f58ae449e05685e59a73e4 (patch) | |
| tree | 66055fd783a6f9ae5d6bbca623849c7517a5d391 /docs/source/glossary.rst | |
| parent | 1f792e6b9c9b41c4da8f8996e3eb325e444b0099 (diff) | |
| parent | 335d9367fd07ebe5da50d2f9e336d5d8f6e31aee (diff) | |
| download | PROJ-0ff11909243616f4b8f58ae449e05685e59a73e4.tar.gz PROJ-0ff11909243616f4b8f58ae449e05685e59a73e4.zip | |
Merge pull request #2127 from rouault/projinfo_hide_ballpark
projinfo: add a --hide-ballpark option
Diffstat (limited to 'docs/source/glossary.rst')
| -rw-r--r-- | docs/source/glossary.rst | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/docs/source/glossary.rst b/docs/source/glossary.rst index 21dd0f34..883460d4 100644 --- a/docs/source/glossary.rst +++ b/docs/source/glossary.rst @@ -6,6 +6,25 @@ Glossary .. glossary:: + Ballpark transformation + + For a transformation between two geographic CRS, a ballpark + transformation is a coordinate operation that only takes into account + potential difference of axis orders (long-lat vs lat-long), + units (degree vs grads) and prime meridian (Greewich vs Paris/Rome/other + historic prime meridians). It does not attempt any datum shift, hence + the "ballpark" qualifier in its name. Its accuracy is unknown, and could + lead in some cases to errors of a few hundreds of metres. + + For a transformation between two vertical CRS or a vertical CRS and + a geogrpahic CRS, a ballpark transformation only takes into account + potential different in units (e.g. metres vs feet). Its accuracy is + unknown, and could lead in some cases to errors of a few tens of metres. + + .. note:: + + The term "Ballpark transformation" is specific to PROJ. + Pseudocylindrical Projection Pseudocylindrical projections have the mathematical characteristics of |