From 7ea472f54849f3230d5865884ef75c4edcda3fa8 Mon Sep 17 00:00:00 2001 From: Kristian Evers Date: Mon, 28 Aug 2017 08:07:48 +0200 Subject: Major restructure and rewrite of docs. A section on "Using PROJ.4" has been introduced giving a introduction on how to use PROJ.4. The Parameters section has been removed and the content reworked into other sections. Additionally the order of chapters has been changed to provide a more complete and readable experience for users of the documentation. --- docs/source/usage/quickstart.rst | 68 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 docs/source/usage/quickstart.rst (limited to 'docs/source/usage/quickstart.rst') diff --git a/docs/source/usage/quickstart.rst b/docs/source/usage/quickstart.rst new file mode 100644 index 00000000..d162ace9 --- /dev/null +++ b/docs/source/usage/quickstart.rst @@ -0,0 +1,68 @@ +.. _quickstart: + +================================================================================ +Quick start +================================================================================ + +Coordinate transformations are defined by, what in PROJ.4 terminology is +known as, "proj-strings". A proj-string describes any transformation regardless of +how simple or complicated it might be. The simplest case is projection of geodetic +coordinates. This section focuses on the simpler cases and introduces the basic +anatomy of the proj-string. The complex cases are discussed in +:doc:`transformation`. + +A proj-strings holds the parameters of a given coordinate transformation, e.g. + +:: + + +proj=merc +lat_ts=56.5 +ellps=GRS80 + +I.e. a proj-string consists of a projection specifier, ``+proj``, a number of +parameters that applies to the projection and, if needed, a description of a +datum shift. In the example above geodetic coordinates are transformed to +projected space with the :doc:`Mercator projection<../projections/merc>` with +the latitude of true scale at 56.5 degrees north on the GRS80 ellipsoid. Every +projection in PROJ.4 is identified by a shorthand such as ``merc`` in the above +example. + +By using the above projection definition as parameters for the command line +utility ``proj`` we can convert the geodetic coordinates to projected space: + +:: + + $ proj +proj=merc +lat_ts=56.5 +ellps=GRS80 + +If called as above ``proj`` will be in interactive mode, letting you type the +input data manually and getting a responce presented on screen. ``proj`` +works as any UNIX filter though, which means that you can also pipe data to +the utility, for instance by using the ``echo`` command: + +:: + + $ echo 55.2 12.2 | proj +proj=merc +lat_ts=56.5 +ellps=GRS80 + 3399483.80 752085.60 + + +PROJ.4 also comes bundled with the ``cs2cs`` utility which is used to transform +from onecoordinate reference system to another. Say we want to convert +the above Mercator coordinates to UTM, we can do that with ``cs2cs``: + +:: + + $ echo 3399483.80 752085.60 | cs2cs +proj=merc +lat_ts=56.5 +ellps=GRS80 +to +proj=utm +zone=32 + 6103992.36 1924052.47 0.00 + +Notice the ``+to`` parameter that seperates the source and destination +projection definitions. + +If you happen to know the EPSG identifiers for the two cordinates reference +systems you are transforming between you can use those with ``cs2cs``: + +:: + + $ echo 56 12 | cs2cs +init=epsg:4326 +to +init=epsg:25832 + 231950.54 1920310.71 0.00 + +In the above example we transform geodetic coordinates in the WGS84 reference +frame to UTM zone 32N coordinates in the ETRS89 reference frame. +UTM coordinates -- cgit v1.2.3 From 082f5aed6ea6a746e73c17e39f8aabb85d840272 Mon Sep 17 00:00:00 2001 From: Kristian Evers Date: Wed, 15 Nov 2017 21:52:25 +0100 Subject: Fix a few bad links [skip ci] --- docs/source/usage/quickstart.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'docs/source/usage/quickstart.rst') diff --git a/docs/source/usage/quickstart.rst b/docs/source/usage/quickstart.rst index d162ace9..96bfbba1 100644 --- a/docs/source/usage/quickstart.rst +++ b/docs/source/usage/quickstart.rst @@ -20,7 +20,7 @@ A proj-strings holds the parameters of a given coordinate transformation, e.g. I.e. a proj-string consists of a projection specifier, ``+proj``, a number of parameters that applies to the projection and, if needed, a description of a datum shift. In the example above geodetic coordinates are transformed to -projected space with the :doc:`Mercator projection<../projections/merc>` with +projected space with the :doc:`Mercator projection` with the latitude of true scale at 56.5 degrees north on the GRS80 ellipsoid. Every projection in PROJ.4 is identified by a shorthand such as ``merc`` in the above example. -- cgit v1.2.3 From 631145da4d23db670cb378fdae14dc6f3555513b Mon Sep 17 00:00:00 2001 From: Kristian Evers Date: Mon, 19 Feb 2018 23:09:40 +0100 Subject: Change most occurences of PROJ.4 to PROJ [skip ci] --- docs/source/usage/quickstart.rst | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'docs/source/usage/quickstart.rst') diff --git a/docs/source/usage/quickstart.rst b/docs/source/usage/quickstart.rst index 96bfbba1..2cf66122 100644 --- a/docs/source/usage/quickstart.rst +++ b/docs/source/usage/quickstart.rst @@ -4,7 +4,7 @@ Quick start ================================================================================ -Coordinate transformations are defined by, what in PROJ.4 terminology is +Coordinate transformations are defined by, what in PROJ terminology is known as, "proj-strings". A proj-string describes any transformation regardless of how simple or complicated it might be. The simplest case is projection of geodetic coordinates. This section focuses on the simpler cases and introduces the basic @@ -22,7 +22,7 @@ parameters that applies to the projection and, if needed, a description of a datum shift. In the example above geodetic coordinates are transformed to projected space with the :doc:`Mercator projection` with the latitude of true scale at 56.5 degrees north on the GRS80 ellipsoid. Every -projection in PROJ.4 is identified by a shorthand such as ``merc`` in the above +projection in PROJ is identified by a shorthand such as ``merc`` in the above example. By using the above projection definition as parameters for the command line @@ -43,7 +43,7 @@ the utility, for instance by using the ``echo`` command: 3399483.80 752085.60 -PROJ.4 also comes bundled with the ``cs2cs`` utility which is used to transform +PROJ also comes bundled with the ``cs2cs`` utility which is used to transform from onecoordinate reference system to another. Say we want to convert the above Mercator coordinates to UTM, we can do that with ``cs2cs``: -- cgit v1.2.3 From be3791ffd5e802d5a3d38fa08f5ed24715b73c7c Mon Sep 17 00:00:00 2001 From: Kristian Evers Date: Wed, 28 Feb 2018 22:37:13 +0100 Subject: Move 'Coordinate operations' to top level of docs [skip ci] --- docs/source/usage/quickstart.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'docs/source/usage/quickstart.rst') diff --git a/docs/source/usage/quickstart.rst b/docs/source/usage/quickstart.rst index 2cf66122..077e970c 100644 --- a/docs/source/usage/quickstart.rst +++ b/docs/source/usage/quickstart.rst @@ -20,7 +20,7 @@ A proj-strings holds the parameters of a given coordinate transformation, e.g. I.e. a proj-string consists of a projection specifier, ``+proj``, a number of parameters that applies to the projection and, if needed, a description of a datum shift. In the example above geodetic coordinates are transformed to -projected space with the :doc:`Mercator projection` with +projected space with the :doc:`Mercator projection<../operations/projections/merc>` with the latitude of true scale at 56.5 degrees north on the GRS80 ellipsoid. Every projection in PROJ is identified by a shorthand such as ``merc`` in the above example. -- cgit v1.2.3