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authorHoward Butler <howard@hobu.co>2016-09-08 17:13:05 -0500
committerHoward Butler <howard@hobu.co>2016-09-08 17:13:05 -0500
commit94142b9061fd1a6ca64e0e7401f2f7d34d1f261e (patch)
tree5e39d6e8967e5684f58c4618696b5f110fe6178d /docs
parent57a07c119ae08945caa92b29c4b427b57f1f728d (diff)
downloadPROJ-94142b9061fd1a6ca64e0e7401f2f7d34d1f261e.tar.gz
PROJ-94142b9061fd1a6ca64e0e7401f2f7d34d1f261e.zip
start plugging in some equations from Gerald's docs
Diffstat (limited to 'docs')
-rw-r--r--docs/source/glossary.rst41
-rw-r--r--docs/source/index.rst1
-rw-r--r--docs/source/projections/eck1.rst14
-rw-r--r--docs/source/projections/fouc_s.rst21
-rw-r--r--docs/source/projections/hatano.rst27
-rw-r--r--docs/source/projections/wag2.rst14
-rw-r--r--docs/source/projections/wag3.rst12
7 files changed, 125 insertions, 5 deletions
diff --git a/docs/source/glossary.rst b/docs/source/glossary.rst
new file mode 100644
index 00000000..92b75ecd
--- /dev/null
+++ b/docs/source/glossary.rst
@@ -0,0 +1,41 @@
+.. _glossary::
+
+================================================================================
+Glossary
+================================================================================
+
+.. glossary::
+
+ Pseudocylindrical Projection
+
+ Pseudocylindrical projections have the mathematical characteristics of
+
+ .. math::
+
+ \begin {array}
+
+ x &= f(\lambda,\phi)
+
+ y &= g(\phi)
+
+ \end {array}
+
+ where the parallels of latitude are straight lines, like cylindrical
+ projections, but the meridians are curved toward the center as they
+ depart from the equator. This is an effort to minimize the distortion
+ of the polar regions inherent in the cylindrical projections.
+
+ Pseudocylindrical projections are almost exclusively used for small
+ scale global displays and, except for the Sinusoidal projection, only
+ derived for a spherical Earth. Because of the basic definition none of
+ the pseudocylindrical projections are conformal but many are equal
+ area.
+
+ To further reduce distortion, pseudocylindrical are often presented in
+ interrupted form that are made by joining several regions with
+ appropriate central meridians and false easting and clipping
+ boundaries. Interrupted Homolosine constructions are suited for showing
+ respective global land and oceanic regions, for example. To reduce the
+ lateral size of the map, some uses remove an irregular, North-South
+ strip of the mid-Atlantic region so that the western tip of Africa is
+ plotted north of the eastern tip of South America.
diff --git a/docs/source/index.rst b/docs/source/index.rst
index 89c60392..7e4d66ec 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -40,6 +40,7 @@ Documentation
threads
parameters
projections/index
+ glossary
diff --git a/docs/source/projections/eck1.rst b/docs/source/projections/eck1.rst
index 71f09733..54fc2f5c 100644
--- a/docs/source/projections/eck1.rst
+++ b/docs/source/projections/eck1.rst
@@ -6,5 +6,17 @@ Eckert I
.. image:: ./images/eck1.png
:scale: 50%
- :alt: Eckert I
+ :alt: Eckert I
+
+
+.. math::
+
+ \begin{array}
+
+ x &= 2 \sqrt{2/3\pi} \lambda (1- |\phi|/\pi)
+
+ y &= 2 \sqrt{2/3\pi}\phi
+
+ \end {array}
+
diff --git a/docs/source/projections/fouc_s.rst b/docs/source/projections/fouc_s.rst
index 5a60d0e7..1c5dffa1 100644
--- a/docs/source/projections/fouc_s.rst
+++ b/docs/source/projections/fouc_s.rst
@@ -6,5 +6,24 @@ Foucaut Sinusoidal
.. image:: ./images/fouc_s.png
:scale: 50%
- :alt: Foucaut Sinusoidal
+ :alt: Foucaut Sinusoidal
+
+The `y`-axis is based upon a weighted mean of the cylindrical equal-area and
+the sinusoidal projections. Parameter :math:`n=n` is the weighting factor where
+:math:`0 <= n <= 1`.
+
+.. math::
+
+ \begin{array}
+
+ x &= \lambda \cos \phi / (n + (1 - n) \ cos \phi)
+
+ y &= n \phi + (1 - n) \sin \phi
+
+ \end {array}
+
+For the inverse, the Newton-Raphson method can be used to determine
+:math:`\phi` from the equation for :math:`y` above. As :math:`n -> 0` and
+:math:`\phi -> \pi/2`, convergence is slow but for :math:`n = 0`, :math:`\phi =
+\sin^1y`
diff --git a/docs/source/projections/hatano.rst b/docs/source/projections/hatano.rst
index 6660a689..eaf7f18b 100644
--- a/docs/source/projections/hatano.rst
+++ b/docs/source/projections/hatano.rst
@@ -6,5 +6,30 @@ Hatano Asymmetrical Equal Area
.. image:: ./images/hatano.png
:scale: 50%
- :alt: Hatano Asymmetrical Equal Area
+ :alt: Hatano Asymmetrical Equal Area
+
+
+:term:`Pseudocylindrical Projection`
+
+.. note::
+
+ If the ``+syn`` option is selected, the symmetric form of this projection is
+ used. Otherwise the asymmetric form is used by default.
+
+.. math::
+
+ \begin{array}
+
+ x &= 0.85\lambda cos \theta
+
+ y &= C_y sin \theta
+
+ P(\theta) &= 2\theta + sin 2\theta - C_p sin \phi
+
+ P'(\theta) &= 2(1 + cos 2\theta)
+
+ \theta_0 &= 2\phi
+
+ \end{array}
+
diff --git a/docs/source/projections/wag2.rst b/docs/source/projections/wag2.rst
index 95063695..f9e71354 100644
--- a/docs/source/projections/wag2.rst
+++ b/docs/source/projections/wag2.rst
@@ -6,5 +6,17 @@ Wagner II
.. image:: ./images/wag2.png
:scale: 50%
- :alt: Wagner II
+ :alt: Wagner II
+
+.. math::
+
+ \begin{array}
+
+ x &= 0.92483 \lambda \cos \theta
+
+ y &= 1.38725\theta
+
+ \sin \theta &= 0.88022 \sin(0.8855\phi)
+
+ \end {array}
diff --git a/docs/source/projections/wag3.rst b/docs/source/projections/wag3.rst
index beae5662..5b043ef4 100644
--- a/docs/source/projections/wag3.rst
+++ b/docs/source/projections/wag3.rst
@@ -6,5 +6,15 @@ Wagner III
.. image:: ./images/wag3.png
:scale: 50%
- :alt: Wagner III
+ :alt: Wagner III
+
+.. math::
+
+ \begin{array}
+
+ x &= [\cos\phi_{ts} / \cos ( 2\phi_{ts} / 3)] \lambda \cos (2\phi /3)
+
+ y = \phi
+
+ \end {array}