From 9750c044740692f757bfd7c6760f69a8683c330a Mon Sep 17 00:00:00 2001 From: Kristian Evers Date: Sat, 7 Dec 2019 19:48:04 +0100 Subject: Add intro and table to isea doc page --- docs/source/operations/projections/isea.rst | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'docs/source/operations') diff --git a/docs/source/operations/projections/isea.rst b/docs/source/operations/projections/isea.rst index 1afedc30..968d468b 100644 --- a/docs/source/operations/projections/isea.rst +++ b/docs/source/operations/projections/isea.rst @@ -4,6 +4,31 @@ Icosahedral Snyder Equal Area ******************************************************************************** +The Icosaheadra Snyder Equal Area projection is a series of equal-area map +projections. Lines of constant distortion follow approximately oval or +rectangular paths instead of the circles of the Lambert Azimuthal Equal-Area +projection or the straight lines of the Cylindrical Equal-Area projection. The +projection series permits design of equal-area maps of oblong regions with less +overall distortion of shape and scale than equal-area maps on other projections +:cite:`Snyder1988`. + ++---------------------+----------------------------------------------------------+ +| **Classification** | Polyhedral, equal Area | ++---------------------+----------------------------------------------------------+ +| **Available forms** | Forward, spherical | ++---------------------+----------------------------------------------------------+ +| **Defined area** | Global | ++---------------------+----------------------------------------------------------+ +| **Alias** | isea | ++---------------------+----------------------------------------------------------+ +| **Domain** | 2D | ++---------------------+----------------------------------------------------------+ +| **Input type** | Geodetic coordinates | ++---------------------+----------------------------------------------------------+ +| **Output type** | Projected coordinates | ++---------------------+----------------------------------------------------------+ + + .. figure:: ./images/isea.png :width: 500 px :align: center -- cgit v1.2.3 From 9b3a80ada06d50feb5cd158dcb807d6942a7b9e4 Mon Sep 17 00:00:00 2001 From: Kristian Evers Date: Mon, 9 Dec 2019 11:46:53 +0100 Subject: isea docs: Rewrite intro and reference to reflect actual projection Previous version was describing oea by mistake. It is also a projection by Snyder and the isea docs was based on the paper on the oea projection. This commit fixes that. --- docs/source/operations/projections/isea.rst | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'docs/source/operations') diff --git a/docs/source/operations/projections/isea.rst b/docs/source/operations/projections/isea.rst index 968d468b..adb703a1 100644 --- a/docs/source/operations/projections/isea.rst +++ b/docs/source/operations/projections/isea.rst @@ -4,16 +4,16 @@ Icosahedral Snyder Equal Area ******************************************************************************** -The Icosaheadra Snyder Equal Area projection is a series of equal-area map -projections. Lines of constant distortion follow approximately oval or -rectangular paths instead of the circles of the Lambert Azimuthal Equal-Area -projection or the straight lines of the Cylindrical Equal-Area projection. The -projection series permits design of equal-area maps of oblong regions with less -overall distortion of shape and scale than equal-area maps on other projections -:cite:`Snyder1988`. +Snyder's Icosahedral Equal Area map projections on polyhedral globes for the +dodecahedron and truncated icosahedron offer relatively low scale and +angular distortion. The equations involved are relatively straight-forward, +and for certain instructional tools and databases, the projections are useful +for world maps. The interruptions remain a disadvantage, as with any low-error +projection system applied to the entire globe :cite:`Snyder1992`. + +---------------------+----------------------------------------------------------+ -| **Classification** | Polyhedral, equal Area | +| **Classification** | Polyhedral, equal area | +---------------------+----------------------------------------------------------+ | **Available forms** | Forward, spherical | +---------------------+----------------------------------------------------------+ -- cgit v1.2.3 From 5be02bf6d1d45ac0d835c138074611843982e9e8 Mon Sep 17 00:00:00 2001 From: Even Rouault Date: Thu, 2 Jan 2020 15:30:19 +0100 Subject: operations_computation.rst: update with latest 6.3 adjustments --- docs/source/operations/operations_computation.rst | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'docs/source/operations') diff --git a/docs/source/operations/operations_computation.rst b/docs/source/operations/operations_computation.rst index 930044e3..ef84cfb2 100644 --- a/docs/source/operations/operations_computation.rst +++ b/docs/source/operations/operations_computation.rst @@ -5,7 +5,7 @@ Computation of coordinate operations between two CRS ================================================================================ :Author: Even Rouault -:Last Updated: 2019-11-28 +:Last Updated: 2020-01-02 Introduction ------------ @@ -41,8 +41,8 @@ geographic CRS: DERIVED_FROM(EPSG):1313, NAD27 to NAD83 (4), 1.5 m, Canada - NAD27, at least one grid missing DERIVED_FROM(EPSG):1241, NAD27 to NAD83 (1), 0.15 m, USA - CONUS including EEZ DERIVED_FROM(EPSG):1243, NAD27 to NAD83 (2), 0.5 m, USA - Alaska including EEZ + DERIVED_FROM(EPSG):1573, NAD27 to NAD83 (6), 1.5 m, Canada - Quebec, at least one grid missing EPSG:1462, NAD27 to NAD83 (5), 1.0 m, Canada - Quebec, at least one grid missing - EPSG:1573, NAD27 to NAD83 (6), 1.5 m, Canada - Quebec, at least one grid missing EPSG:9111, NAD27 to NAD83 (9), 1.5 m, Canada - Saskatchewan, at least one grid missing unknown id, Ballpark geographic offset from NAD27 to NAD83, unknown accuracy, World, has ballpark transformation EPSG:8555, NAD27 to NAD83 (7), 0.15 m, USA - CONUS and GoM, at least one grid missing @@ -236,7 +236,7 @@ are equivalent for most purposes. .. code-block:: shell - $ projinfo projinfo -s EPSG:7042 -t EPSG:4936 + $ projinfo -s EPSG:7042 -t EPSG:4936 Candidate operations found: 1 ------------------------------------- @@ -304,12 +304,12 @@ the source and target CRS, and inverting the resulting operation(s): $ projinfo -s NAD83 -t NAD27 --spatial-test intersects --summary Candidate operations found: 10 - INVERSE(DERIVED_FROM(EPSG)):1312, Inverse of NAD27 to NAD83 (3), 1.0 m, Canada + INVERSE(DERIVED_FROM(EPSG)):1312, Inverse of NAD27 to NAD83 (3), 2.0 m, Canada + INVERSE(DERIVED_FROM(EPSG)):1313, Inverse of NAD27 to NAD83 (4), 1.5 m, Canada - NAD27 INVERSE(DERIVED_FROM(EPSG)):1241, Inverse of NAD27 to NAD83 (1), 0.15 m, USA - CONUS including EEZ INVERSE(DERIVED_FROM(EPSG)):1243, Inverse of NAD27 to NAD83 (2), 0.5 m, USA - Alaska including EEZ - INVERSE(DERIVED_FROM(EPSG)):1313, Inverse of NAD27 to NAD83 (4), 1.5 m, Canada - NAD27, at least one grid missing - INVERSE(EPSG):1462, Inverse of NAD27 to NAD83 (5), 1.0 m, Canada - Quebec, at least one grid missing - INVERSE(EPSG):1573, Inverse of NAD27 to NAD83 (6), 1.5 m, Canada - Quebec, at least one grid missing + INVERSE(DERIVED_FROM(EPSG)):1573, Inverse of NAD27 to NAD83 (6), 1.5 m, Canada - Quebec, at least one grid missing + INVERSE(EPSG):1462, Inverse of NAD27 to NAD83 (5), 2.0 m, Canada - Quebec, at least one grid missing INVERSE(EPSG):9111, Inverse of NAD27 to NAD83 (9), 1.5 m, Canada - Saskatchewan, at least one grid missing unknown id, Ballpark geographic offset from NAD83 to NAD27, unknown accuracy, World, has ballpark transformation INVERSE(EPSG):8555, Inverse of NAD27 to NAD83 (7), 0.15 m, USA - CONUS and GoM, at least one grid missing -- cgit v1.2.3