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A Rasterio dataset's index() method gives you the row, col index of the pixel containing the point x, y (in the dataset's CRS units).

Define a 1x1 pixel read window starting at that index (see the tiny_window() function below) and use it to read an ndarray. The one in this case has shape (3, 1, 1): 3 bands, 1 row, and 1 column. The values of the 3 bands at the point x, y for this case are 28, 29, and 27.

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# 15 statement in this Fiona script, 12 after I move the prop_type function to Fiona.
# Compare to 31 statements for the ogr.py script at
# http://pcjericks.github.io/py-gdalogr-cookbook/layers.html#create-a-new-shapefile-and-add-data.
# The difference is that Fiona's schema and feature definition are declarative (using dict 
# literals and comprehensions, not imperative (CreateField, SetField, etc) and that Fiona
# is designed to allow concise code.

from csv import DictReader
import fiona
from fiona.crs import from_epsg

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Latency Comparison Numbers
--------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

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# Comparing serialization of complex GeoJSON geometries using:
# 
# - standard lib json, marshal, pickle, cPickle
# - umsgpack
# - shapely.wkb
# - geobuf (protobuf)
#
# The test case is a nearly circular polygon with 128 vertices.
#
# Python 2.7 because geobuf isn't possible on Python 3 (because

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{
 "metadata": {
  "name": "Unary union example"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {

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{"geometry": {"coordinates": [[[-111.73527526855469, 41.995094299316406], [-111.65931701660156, 41.99627685546875], [-111.6587142944336, 41.9921875], [-111.65888977050781, 41.95676803588867], [-111.67082977294922, 41.91230010986328], [-111.67332458496094, 41.905494689941406], [-111.67088317871094, 41.90049362182617], [-111.66474914550781, 41.893211364746094], [-111.6506576538086, 41.875465393066406], [-111.64759826660156, 41.87091827392578], [-111.64640808105469, 41.86273956298828], [-111.64334869384766, 41.858192443847656], [-111.63720703125, 41.85499572753906], [-111.633544921875, 41.847267150878906], [-111.63053894042969, 41.83409118652344], [-111.6330337524414, 41.82728576660156], [-111.63983154296875, 41.8227653503418], [-111.6484603881836, 41.82188034057617], [-111.66077423095703, 41.82327651977539], [-111.6712417602539, 41.82330322265625], [-111.67618560791016, 41.82013702392578], [-111.68803405761719, 41.78792953491211], [-111.69361114501953, 41.77931594848633], [-111.70162200927734, 41.77797317504883

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vas-y:parallelz seang$ time parallel wc ::: `find ~/writing/blog/2013 -name *.rst`
      18     128     791 /Users/seang/writing/blog/2013/10/07/downgrading-my-blog.rst
     106     567    4011 /Users/seang/writing/blog/2013/10/08/linking-geojson.rst
      34     249    1586 /Users/seang/writing/blog/2013/10/24/joining-mapbox.rst
      70     373    2910 /Users/seang/writing/blog/2013/11/24/introducing-rasterio.rst
      14      45     395 /Users/seang/writing/blog/2013/12/02/geojson-website-refreshed.rst
      25     158    1256 /Users/seang/writing/blog/2013/12/03/atom-extension-for-tinkerer.rst
      16      74     627 /Users/seang/writing/blog/2013/11/27/new-home-on-github-for-geojson.rst
     143     685    6211 /Users/seang/writing/blog/2013/12/04/json-diff-and-patch-for-geojson.rst
      26     202    1237 /Users/seang/writing/blog/2013/12/05/first-blog-post-at-mapbox.rst

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#!/bin/bash

export MACOSX_DEPLOYMENT_TARGET=10.6
export ARCHFLAGS="-arch i386 -arch x86_64"

# GEOS from source.
cd ~/work/geos-3.4.2
./configure CFLAGS="-Os -arch i386 -arch x86_64" CXXFLAGS="-Os -arch i386 -arch x86_64" LDFLAGS="-arch i386 -arch x86_64"
make clean
make