Maps
New Organizing Institute
Data Bootcamp 2014
Noah Glusenkamp
cofounder | Empower Engine
ObjectiveS
By the end of today you will be able to:
- make maps!
- advocate for time /resources to make maps
- see the range of what's possible with geo-spatial
- find where to learn more
WHy Make maps?
Maps Help US
- communicate information quickly
- see geographic patterns in data
- office locations
- volunteer to voter demographics pairing
- motivate people
- this is near me, this is possible
- I'm a part of this, I belong
- this region needs to do more work
- convince people
- model scores & local geo-based knowledge
- debug field programs
There's
no such thing
as a
viral excel sheet
- Ben Blatt, Slate
>
*sometimes
Prop 1: Car Tabs Increase for TRANSIT
King County, WA (2014)
Map by Benjamin Anderstone, anderstone.com
Number of Jobs Accessible by Transit
Map by Brandon Martin-Anderson, Conveyal
"Our displays of evidence
should be worthy of the
spectacular resolution
of the human eye-brain system"
- Edward Tufte
Spatial Data
raster
image from mapschool.io
Spatial Data
vector
image from mapschool.io
Latitude & Longitude
image from mapschool.io
Geocodes
look up the lat, lon for and address
GEOCODES
Allow you to put points on a map
Free Geocoders:
gpsvizualizer.com, Texas A&M, Census Bureau, PostGIS Tiger Geocoder
Vector Data Formats
Shapefile
WI_precincts.zip contains:
WI_precincts.shp
WI_precincts.prj
WI_precincts.shx
WI_precincts.dbf
GeoJSON, KML
Projections
it turns out that
the earth is not a perfect sphere
image from giscommons.org/earth-and-map-preprocessing
PROJECTIONS
and maps are usually 2D "flatland"
image from kidsgeo.com
PROJECTIONS
Map data usually comes in a certain projection.
The projection you use determines your distance units.
The important thing is to make sure you're using the same projection when mapping two data sets.
PROJECTIONS
thankfully, QGIS makes this easy to do
Features and Attributes
image from www.indiana.edu/~gisci/courses/g338/lectures/attributes.html
QGIS ExerCISE
FEATURES AND ATTRIBUTES
image from www.indiana.edu/~gisci/courses/g338/lectures/attributes.html
...or Just Rows with
A COLUMN FOr GEOMETRY
Spatial Database
Oracle Spatial, SQLServer Spatial
ESRI Personal Geodatabase (.mdb), SpatialLite
Querying
in QGIS
"num_persons" < 500
Spatial JoinS
location is the universal key
e.g. points in polygon
apply districts, aggregate values/counts
image from http://wtlab.iis.u-tokyo.ac.jp/~wataru/lecture/rsgis/giswb/vol2/cp4/cp4-7.htm
Spatial JOins
or
UPDATE hex.wa_voters_lat_long
SET prec_2013_district_id=precincts_2013.district_id
FROM hex.precincts_2013
WHERE ST_CONTAINS(precincts_2013.geometry, wa_voters_lat_long.point); There's Plenty More to learn
Map Design
symbology, data classification, color schemes/scales
Spatial Analysis
buffers, complex joins, view-sheds
Spatial statistics / machine learning
surfaces & other crazy-raw shit
Making Maps
By Noah Glusenkamp
Making Maps
Making maps - 2014 NOI Data Bootcamp GIS session 1
