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source: trunk/workshop-foss4g/about_data.rst @ 12

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[1]1.. _about_data:
2
3Section 5: About our data
4=========================
5
6The data for this workshop is four shapefiles for New York City, and one attribute table of sociodemographic variables.  We've loaded our shapefiles as PostGIS tables and will add sociodemographic data later in the workshop.
7
8The following describes the number of records and table attributes for each of our datasets.  These attribute values and relationships are fundamental to our future analysis.
9
10To explore the nature of your tables in pgAdmin, right-click a highlighted table and select **Properties**.  You will find a summary of table properties, including a list of table attributes within the **Columns** tab.
11
12nyc_census_blocks
13-----------------
14
15A census block is the smallest geography for which census data is reported. All higher level census geographies (block groups, tracts, metro areas, counties, etc) can be built from unions of census blocks. We have attached some demographic data to our collection of blocks.
16
17Number of records: 36592
18
19.. list-table::
20   :widths: 20 80
21
22   * - **blkid**
23     - A 15-digit code that uniquely identifies every census **block**. Eg: 360050001009000
24   * - **popn_total**
25     - Total number of people in the census block
26   * - **popn_white**
27     - Number of people self-identifying as "White" in the block
28   * - **popn_black**
29     - Number of people self-identifying as "Black" in the block
30   * - **popn_nativ**
31     - Number of people self-identifying as "Native American" in the block
32   * - **popn_asian**
33     - Number of people self-identifying as "Asian" in the block
34   * - **popn_other**
35     - Number of people self-identifying with other categories in the block
36   * - **hous_total**
37     - Number of housing units in the block
38   * - **hous_own**
39     - Number of owner-occupied housing units in the block
40   * - **hous_rent**
41     - Number of renter-occupied housing units in the block
42   * - **boroname**
43     - Name of the New York borough. Manhattan, The Bronx, Brooklyn, Staten Island, Queens
44   * - **the_geom**
45     - Polygon boundary of the block
46
47.. figure:: ./screenshots/nyc_census_blocks.png
48   
49   *Black population as a percentage of Total Population* 
50
51.. note:: 
52
53    To get census data into GIS, you need to join two pieces of information: the actual data (text), and the boundary files (spatial).  There are many options for getting the data, including downloading data and boundaries from the Census Bureau's `American FactFinder <http://factfinder.census.gov>`_.
54   
55nyc_neighborhoods
56-----------------
57
58New York has a rich history of neighborhood names and extent.  Neighborhoods are social constructs that do not follow lines laid down by the government. For example, the Brooklyn neighborhoods of Carroll Gardens, Red Hook, and Cobble Hill were once collectively known as "South Brooklyn." And now, depending on which real estate agent you talk to, the same four blocks in the-neighborhood-formerly-known-as-Red-Hook can be referred to as Columbia Heights, Carroll Gardens West, or Red Hook!
59
60Number of records: 129
61
62.. list-table::
63   :widths: 20 80
64
65   * - **name**
66     - Name of the neighborhood
67   * - **boroname**
68     - Name of the New York borough. Manhattan, The Bronx, Brooklyn, Staten Island, Queens
69   * - **the_geom**
70     - Polygon boundary of the neighborhood
71   
72.. figure:: ./screenshots/nyc_neighborhoods.png
73
74    *The neighborhoods of New York City* 
75
76nyc_streets
77-----------
78
79The street centerlines form the transportation network of the city. These streets have been flagged with types in order to distinguish between such thoroughfares as back alleys, arterial streets, freeways, and smaller streets. Desirable areas to live might be on residential streets rather than next to a freeway.
80
81Number of records: 19091
82
83.. list-table::
84   :widths: 20 80
85
86   * - **name**
87     - Name of the street
88   * - **oneway**
89     - Is the street one-way? "yes" = yes, "" = no
90   * - **type**
91     - Road type. Eg. primary, secondary, residential, motorway
92   * - **the_geom**
93     - Linear centerline of the street
94   
95.. figure:: ./screenshots/nyc_streets.png
96
97     *The streets of New York City. Major roads are in red.*
98
99   
100nyc_subway_stations
101-------------------
102
103The subway stations link the upper world where people live to the invisible network of subways beneath. As portals to the public transportation system, station locations help determine how easy it is for different people to enter the subway system.
104
105Number of records: 491
106
107.. list-table::
108   :widths: 20 80
109
110   * - **name**
111     - Name of the station
112   * - **borough**
113     - Name of the New York borough. Manhattan, The Bronx, Brooklyn, Staten Island, Queens
114   * - **routes**
115     - Subway lines that run through this station
116   * - **transfers**
117     - Lines you can transfer to via this station
118   * - **express**
119     - Stations where express trains stop, "express" = yes, "" = no
120   * - **the_geom**
121     - Point location of the station
122
123.. figure:: ./screenshots/nyc_subway_stations.png
124
125    *Point locations for New York City subway stations*
126
127nyc_census_sociodata
128--------------------
129
130There is a rich collection of social-economic data collected during the census process, but only at the larger geography level of census tract.  Census blocks combine to form census tracts (and block groups). We have collected some social-economic at a census tract level to answer some of these more interesting questions about New York City.
131
132.. note::
133
134   The ``nyc_census_sociodata`` is a data table.  We will need to connect it to Census geographies before conducting any spatial analysis.
135
136.. list-table::
137   :widths: 20 80
138
139   * - **tractid**
140     - An 11-digit code that uniquely identifies every census **tract**. Eg: 36005000100
141   * - **transit_total**
142     - Number of workers in the tract
143   * - **transit_public**
144     - Number of workers in the tract who take public transit
145   * - **transit_private**
146     - Number of workers in the tract who use private automobiles / motorcycles
147   * - **transit_other**
148     - Number of workers in the tract who use other forms like walking / biking
149   * - **transit_time_mins**
150     - Total number of minutes spent in transit by all workers in the tract (minutes)
151   * - **family_count**
152     - Number of familes in the tract
153   * - **family_income_median**
154     - Median family income in the tract (dollars)
155   * - **family_income_aggregate**
156     - Total income of all families in the tract (dollars)
157   * - **edu_total**
158     - Number of people with educational history
159   * - **edu_no_highschool_dipl**
160     - Number of people with no highschool diploma
161   * - **edu_highschool_dipl**
162     - Number of people with highschool diploma and no further education
163   * - **edu_college_dipl**
164     - Number of people with college diploma and no further education
165   * - **edu_graduate_dipl**
166     - Number of people with graduate school diploma
167
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