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Diffstat (limited to 'docs/source/operations/conversions')
| -rw-r--r-- | docs/source/operations/conversions/axisswap.rst | 39 | ||||
| -rw-r--r-- | docs/source/operations/conversions/cart.rst | 24 | ||||
| -rw-r--r-- | docs/source/operations/conversions/index.rst | 18 | ||||
| -rw-r--r-- | docs/source/operations/conversions/latlon.rst | 6 | ||||
| -rw-r--r-- | docs/source/operations/conversions/lonlat.rst | 6 | ||||
| -rw-r--r-- | docs/source/operations/conversions/unitconvert.rst | 112 |
6 files changed, 205 insertions, 0 deletions
diff --git a/docs/source/operations/conversions/axisswap.rst b/docs/source/operations/conversions/axisswap.rst new file mode 100644 index 00000000..ddaad075 --- /dev/null +++ b/docs/source/operations/conversions/axisswap.rst @@ -0,0 +1,39 @@ +.. _axisswap: + +================================================================================ +Axis swap +================================================================================ + +Change the order and sign of 2,3 or 4 axes. + ++--------------+---------------------------------------------------------------+ +| **Options** | ++--------------+---------------------------------------------------------------+ +| `+order` | Ordered comma-separated list of axis, e.g. `+order=2,1,3,4` | ++--------------+---------------------------------------------------------------+ + + +Each of the possible four axes are numbered with 1-4, such that the first input axis +is 1, the second is 2 and so on. The output ordering is controlled by a list of the +input axes re-ordered to the new mapping. + +Examples +################################################################################ + +Reversing the order of the axes:: + + +proj=axisswap +order=4,3,2,1 + +Swapping the first two axes (x and y):: + + +proj=axisswap +order=2,1,3,4 + +The direction, or sign, of an axis can be changed by adding a minus in +front of the axis-number:: + + +proj=axisswap +order=1,-2,3,4 + +It is only necessary to specify the axes that are affected by the swap +operation:: + + +proj=axisswap +order=2,1 diff --git a/docs/source/operations/conversions/cart.rst b/docs/source/operations/conversions/cart.rst new file mode 100644 index 00000000..0c3c7c23 --- /dev/null +++ b/docs/source/operations/conversions/cart.rst @@ -0,0 +1,24 @@ +.. _cart: + +================================================================================ +Cartesian to geodetic conversion +================================================================================ + +Convert geodetic coordinates to cartesian coordinates. + ++--------------+--------------------------------------------------------------------+ +| **Options** | ++--------------+--------------------------------------------------------------------+ +| `+ellps` | Ellipsoid of the input coordinates. If used together with the | +| | ellipsoid parameters below, ``+ellps`` is overwritten. | ++--------------+--------------------------------------------------------------------+ +| `+a` | Semi-major radius of ellipsoid axis. | ++--------------+--------------------------------------------------------------------+ +| `+b` | Semi-minor radius of ellipsoid axis. | ++--------------+--------------------------------------------------------------------+ +| `+es` | Eccentricity of ellipsoid. | ++--------------+--------------------------------------------------------------------+ +| `+f` | Flattening of ellipsoid. | ++--------------+--------------------------------------------------------------------+ + + diff --git a/docs/source/operations/conversions/index.rst b/docs/source/operations/conversions/index.rst new file mode 100644 index 00000000..af27e2fd --- /dev/null +++ b/docs/source/operations/conversions/index.rst @@ -0,0 +1,18 @@ +.. _conversions_list: + +================================================================================ +Conversions +================================================================================ + +Conversions are coordinate operations in which both coordinate reference systems +are based on the same datum. In PROJ projections are differentiated from +conversions. + +.. toctree:: + :maxdepth: 1 + + axisswap + cart + lonlat + latlon + unitconvert diff --git a/docs/source/operations/conversions/latlon.rst b/docs/source/operations/conversions/latlon.rst new file mode 100644 index 00000000..6712fa7b --- /dev/null +++ b/docs/source/operations/conversions/latlon.rst @@ -0,0 +1,6 @@ +.. _latlon: + +******************************************************************************** +Lat/long (Geodetic alias) +******************************************************************************** + diff --git a/docs/source/operations/conversions/lonlat.rst b/docs/source/operations/conversions/lonlat.rst new file mode 100644 index 00000000..589cc813 --- /dev/null +++ b/docs/source/operations/conversions/lonlat.rst @@ -0,0 +1,6 @@ +.. _lonlat: + +******************************************************************************** +Lat/long (Geodetic) +******************************************************************************** + diff --git a/docs/source/operations/conversions/unitconvert.rst b/docs/source/operations/conversions/unitconvert.rst new file mode 100644 index 00000000..73e517bd --- /dev/null +++ b/docs/source/operations/conversions/unitconvert.rst @@ -0,0 +1,112 @@ +.. _unitconvert: + +================================================================================ +Unit conversion +================================================================================ + +Convert between various distance and time units. + ++--------------+--------------------------------------------------------------------+ +| **Options** | ++--------------+--------------------------------------------------------------------+ +| `+xy_in` | Input unit of the horizontal components. | ++--------------+--------------------------------------------------------------------+ +| `+xy_out` | Output unit of the horizontal components. | ++--------------+--------------------------------------------------------------------+ +| `+z_in` | Input unit of the vertical component. | ++--------------+--------------------------------------------------------------------+ +| `+z_out` | Output unit of the vertical component. | ++--------------+--------------------------------------------------------------------+ +| `+t_in` | Input unit of the time component. | ++--------------+--------------------------------------------------------------------+ +| `+t_out` | Output unit of the time component. | ++--------------+--------------------------------------------------------------------+ + +There are many examples of coordinate reference systems that are expressed in +other units than the meter. There are also many cases where temporal data +has to be translated to different units. The `unitconvert` operation takes care +of that. + +Many North American systems are defined with coordinates in feet. For example +in Vermont:: + + +proj=pipeline + +step +proj=tmerc +lat_0=42.5 +lon_0=-72.5 +k=0.999964286 +x_0=500000.00001016 +y_0=0 + +step +proj=unitconvert +xy_in=m +xy_out=us-ft + +Often when working with GNNS data the timestamps are presented in GPS-weeks, +but when the data transformed with the `helmert` operation timestamps are +expected to be in units of decimalyears. This can be fixed with `unitconvert`:: + + +proj=pipeline + +step +proj=unitconvert +t_in=gpsweek +t_out=decimalyear + +step +proj=helmert +epoch=2000.0 +t_obs=2017.5 ... + + +Distance units +############################################################################### + +In the table below all distance units supported by PROJ is listed. +The same list can also be produced on the command line with `proj` or `cs2cs`, +by adding the `-lu` flag when calling the utility. + ++----------+---------------------------------+ +| Label | Name | ++----------+---------------------------------+ +| km | Kilometer | ++----------+---------------------------------+ +| m | Meter | ++----------+---------------------------------+ +| dm | Decimeter | ++----------+---------------------------------+ +| cm | Centimeter | ++----------+---------------------------------+ +| mm | Millimeter | ++----------+---------------------------------+ +| kmi | International Nautical Mile | ++----------+---------------------------------+ +| in | International Inch | ++----------+---------------------------------+ +| ft | International Foot | ++----------+---------------------------------+ +| yd | International Yard | ++----------+---------------------------------+ +| mi | International Statute Mile | ++----------+---------------------------------+ +| fath | International Fathom | ++----------+---------------------------------+ +| ch | International Chain | ++----------+---------------------------------+ +| link | International Link | ++----------+---------------------------------+ +| us-in | U.S. Surveyor's Inch | ++----------+---------------------------------+ +| us-ft | U.S. Surveyor's Foot | ++----------+---------------------------------+ +| us-yd | U.S. Surveyor's Yard | ++----------+---------------------------------+ +| us-ch | U.S. Surveyor's Chain | ++----------+---------------------------------+ +| us-mi | U.S. Surveyor's Statute Mile | ++----------+---------------------------------+ +| ind-yd | Indian Yard | ++----------+---------------------------------+ +| ind-ft | Indian Foot | ++----------+---------------------------------+ +| ind-ch | Indian Chain | ++----------+---------------------------------+ + + +Time units +############################################################################### + +In the table below all time units supported by PROJ is listed. + ++--------------+-----------------------------+ +| mjd | Modfied Julian date | ++--------------+-----------------------------+ +| decimalyear | Decimal year | ++--------------+-----------------------------+ +| gps_week | GPS Week | ++--------------+-----------------------------+ + |