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Merged branches, added TODO notes and more information to the README

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1 parent 76006a2 commit 29bd26f0c30ba6329bf89d2aced4ad5575b1ab26 @wildintellect committed Apr 17, 2012
Showing with 33 additions and 5 deletions.
  1. +28 −4 README.md
  2. BIN images/robinson_30d_compare.png
  3. +5 −1 pygraticule.py
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@@ -1,12 +1,31 @@
+PyGraticule
+================
+
#About
Python script to generate a graticule that will project cleanly (with smooth arcs) at world scale. The graticule should have a dense distribution of internal nodes along it's line, especially along the ±180, ±90 WGS84 bounding box.
-Output format is geojson, because it's easy to write as a text file in python. Use ogr2ogr to convert to a SHP file.
+##History
+
+Script was originally written as a demonstration for students in Intro to GIS programming with python. Output format is geojson, because it's easy to write as a text file in python. Use ogr2ogr to convert to a SHP file.
+
+##License
By **Alex Mandel** Copyright 2012.
Modifications by Nathaniel Vaughn KELSO.
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+
#Usage
`python pygraticule.py -s 1 -o outfile.geojson`
@@ -22,6 +41,8 @@ There are two script arguments for controlling the density of nodes and the outp
* The output is a GeoJSON format file, not a SHP format Esri Shapefile.
+* Graticule is created in local coordinates (purely numeric).
+
## Examples
When we project out of WGS84 to another coordinate system that is not cylindrical, we need to have enough intermediate nodes
@@ -30,12 +51,15 @@ so we need to add these extra nodes in the raw geodata.
Here we see Robinson using enough nodes:
-![Zoom previews](https://github.com/nvkelso/pygraticule/raw/master/images/robinson.png)
+![Zoom previews](https://github.com/wildintellect/pygraticule/raw/master/images/robinson.png)
Box results when nodes are sparse:
-![Zoom previews](https://github.com/nvkelso/pygraticule/raw/master/images/box_no_densification.png)
+![Zoom previews](https://github.com/wildintellect/pygraticule/raw/master/images/box_no_densification.png)
The two superimposed:
-![Zoom previews](https://github.com/nvkelso/pygraticule/raw/master/images/robinson_plus_box.png)
+![Zoom previews](https://github.com/wildintellect/pygraticule/raw/master/images/robinson_plus_box.png)
+
+Comparison to QGIS graticule creator which only makes nodes where lines intersect:
+![Zoom previews](https://github.com/wildintellect/pygraticule/raw/master/images/robinson_30d_compare.png)
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@@ -21,6 +21,8 @@
import os, stat
from optparse import OptionParser
+#TODO: Take bounding box as arg for setting range
+
parser = OptionParser(usage="""%prog [options]
Generates a GeoJSON file with graticules spaced at specified interval.""")
@@ -31,6 +33,7 @@
parser.add_option('-o', dest='outfilename', default='',
help='Output filename (with or without path), defaults to "graticule_1dd.geojson".')
+#TODO: Implement python OGR writing for multiple output format support.
#parser.add_option('-p', '--shp', dest='shapefile', default=False, type='boolean",
# help='Output a SHP file, defaults to False and requires ORG/GDAL.')
@@ -39,6 +42,7 @@
#set the stepping of the increment, converting from string to interger
+#TODO: Calculate a node density based on the bounding box and interval defined by the user
step = options.step_interval
# destination file
out_file = options.outfilename
@@ -137,4 +141,4 @@
# try:
# ogr2ogr -f "ESRI Shapefile" out_file out_file
# except:
-# pass
+# pass

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