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GIS in the Sciences
ERTH 4750 (38031)
Literate Programming
and the Process of GIS
Steve Signell, Instructor ([email protected])
Robert Poirier, TA ([email protected])
School of Science
Rensselaer Polytechnic Institute
Monday, March 17, 2014
Literate Programming
The process of GIS
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What is the task?
What data do I need
What analyses do I need to perform.
How is the data to be presented
(Maps/Reports/Web applications…)
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The process of GIS
One example in action…
The process of GIS
The process of GIS
One question that immediately comes to mind with this
dataset is "just how many Ecocodes, Domains, Divisions,
Provinces, and Sections are present in this map?"
Fortunately, we can answer this with a simple SQL query.
The process of GIS
Here is SQL that gives a table of names of the domains,
along with area in km
The process of GIS
Here is SQL that gives you a map of the domains
The process of GIS
Here is SQL that gives a table of names of the divisions,
along with area in km
The process of GIS
Here is SQL that gives you a map of the divisions
The process of GIS
Example, continued…
Projects & Grading: Review
Short written assignments & quizzes (25%)
Participation in lab, lecture & group project (25%)
Individual project (50%)
Vector and raster data
Written & Oral Reports
Must have dynamic web map component
Group Projects
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Several layers: vector and/or raster
3-4 data analysis components.
Basic web map with layers & layer selector.
Various assignments along the way
Individual Projects
Most proposals are very ambitious– this is good!
Doing the following will get you 75%:
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Several vector & at least one raster component (or vice versa)
3-4 data analysis components.
Written report with static (print) maps. This will be in the style of literate
programming.
Basic web map with layers & layer selector.
Oral report (~7 minutes, last day of class)
Remaining 25%-- excel in one or more areas:
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Data Analysis
Written Report
Static Maps
Web Map
Oral report
Individual Projects
Individual Projects
Individual Projects
Individual Projects
Individual Projects
Individual Projects
Individual Projects
Homework
Homework for Thursday
• Sections 10-13, 18-19, Boundless PostGIS
Tutorial
http://workshops.boundlessgeo.com/postgis-intro/
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Homework
Homework: quick overview--demo
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Tip: Loading PostGIS layers in QGIS
I’ve found the DB Manager to work best
(DatabaseDB Manager).
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Tip: Loading PostGIS layers in QGIS
I’ve found the DB Manager to work best
(DatabaseDB Manager).
• Click and drag layers to add to map.
• SQL window is awesome...
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Tip: DB Manager SQL Window
DB Manager SQL window is awesome...
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Tip: DB Manager SQL Window
DB Manager SQL window is awesome...
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Tip: Getting PostGIS views to work in
QGIS
This will not work in QGIS because QGIS requires a
primary key
CREATE OR REPLACE VIEW orangeline AS
SELECT nyc_subway_stations.geom,
nyc_subway_stations.color,
nyc_subway_stations.name
FROM nyc_subway_stations
WHERE nyc_subway_stations.color::text = 'ORANGE’
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Tip: Getting PostGIS views to work in
QGIS
Add the red highlighted code to make a fake primary key
CREATE OR REPLACE VIEW orangeline AS
SELECT nyc_subway_stations.geom,
nyc_subway_stations.color,
nyc_subway_stations.name,
row_number() OVER() AS id_qgis
FROM nyc_subway_stations
WHERE nyc_subway_stations.color::text = 'ORANGE’
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