Transcript - Rensselaer Polytechnic Institute

GIS in the Sciences
ERTH 4750 (38031)
Introduction to
Geographic Information Systems
Steve Signell, Instructor ([email protected])
Robert Poirier, TA ([email protected])
School of Science
Rensselaer Polytechnic Institute
Thursday, January 23, 2013
Acknowledgements
• This lecture is partly based on:
– Huisman, O., de By, R.A. (eds.), 2009. Principles of
Geographic Information Systems. ITC Press,
Enschede, The Netherlands
– Fox, P., 2012. Introduction to Geographic Information
Systems for Science. Course lecture at RPI, Troy
– Xiaogang (Marshall) Ma, 2013. Introduction to
Geographic Information Systems for Science. Course
lecture at RPI, Troy
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Contents
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Introductions
Course outline
Logistics and resources
Assessment and assignments
Goals and learning objectives
Introduction to GIS
Next classes
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Introductions
• Instructor: Steve Signell
• TA: Robert Poirier
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Introductions
• Name, major, year.
• Interests, goals, outcomes
• Classes or experience in:
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Geography, cartography
Other spatial analysis
Web development (html, javascript)
Mathematics
• Smart phones?
• Questions
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Logistics
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Class: ERTH 4750
Hours: 10am-11:50pm Monday, Thursday
Location: DCC 232
Instructor: Steve Signell – [email protected]
Contact hours: by appointment
Contact location:
TA: Robert Poirier, [email protected]
Web: http://tw.rpi.edu/web/Courses/GIScience/2014
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Schedule, syllabus, reading, assignments, etc.
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Course Outline (tentative)
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Week 1 (Jan. 23) Introduction to Geographic Information Systems
Week 2 (Jan. 27/Jan. 30) GIS I: Projections & vector data with Qgis
Week 3 (Feb. 3/Feb. 6) GIS II: Raster Analysis with Qgis
Week 4 (Feb 10/Feb. 13) Geodata I: Scrounging 101, tracking down Geodata
Week 5 (Feb. 18/Feb. 20) Geodata II: Mobile data collection*
Week 6 (Feb. 24/Feb. 27) Introduction to Spatial Databases
Week 7 (Mar. 3/Mar. 6) Spatial Queries in PostGIS
Week 8 (Mar. 10/Mar. 13) no classes - spring break
Week 9 (Mar. 17/Mar. 20):Collaborative GIS I: Literate Programming & GitHub
Week 10 (Mar. 24/Mar. 27) Geodata on the Web I: Geoserver, Google, CartoDB
Week 11 (Mar 31/Apr. 3) Geodata on the Web II: Leaflet.js & D3.js
Week 12 (Apr. 7/Apr. 10) Collaborative GIS II: Web Map Mashup
Week 13 (Apr. 14/Apr. 17) Multidimensional data I: Ocean Data View*
Week 14 (Apr. 21/Apr.24) Multidimensional data II: 3D Visualization*
Week 15 (Apr. 28/May 1) Wrap up: Review & the future of GIS
Week 16 (May 5): Monday: Final project presentations
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Assessment and Assignments
• 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
• Late submission policy: first time with valid reason – no
penalty, otherwise 20% of score deducted each late day
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Assessment and Assignments
• Reading assignments
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Are given almost every week
Most are background and informational
Some are key to completing assignments
Some are relevant to the current week’s class (i.e. follow up
reading)
– Others are relevant to following week’s class (i.e. pre-reading)
– Undergraduates - will not be evaluated on but we will often discuss
these in class and participation in these is taken into account
– Graduates – are likely to be tested as part of assignments, i.e. an
extra question
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Goals
• To provide students an opportunity to learn geospatial
applications and tools.
• To introduce relational analysis and interpretation of
spatial data and presentation on maps.
• Introduce spatial database concepts and technical aspects
of query languages and geographic integration of graphic
and tabular data.
• To introduce intermediate aspects of geospatial
analysis: map projections, vectors & geoprocessing, raster
analysis, collaborative mapping, GIS on the cloud and web
mapping.
• To gain experience in end-to-end GIS applications via
group and individual term projects.
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Learning Objectives
• Through class lectures, practical sessions, written
and oral presentation assignments and projects,
students should:
– Demonstrate proficiency in using geospatial
applications and tools (commercial and open-source).
– Present verbally relational analysis and interpretation of
a variety of spatial data on maps.
– Demonstrate skill in applying database concepts to
build and manipulate a spatial database, SQL, spatial
queries, and integration of graphic and tabular data.
– Demonstrate intermediate knowledge of geospatial
analysis methods and their applications.
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Academic Integrity
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Student-teacher relationships are built on trust. For example, students must
trust that teachers have made appropriate decisions about the structure and
content of the courses they teach, and teachers must trust that the
assignments that students turn in are their own. Acts, which violate this trust,
undermine the educational process. The Rensselaer Handbook of Student
Rights and Responsibilities defines various forms of Academic Dishonesty and
you should make yourself familiar with these. In this class, all assignments that
are turned in for a grade must represent the student’s own work. In cases
where help was received, or teamwork was allowed, a notation on the
assignment should indicate your collaboration. Submission of any assignment
that is in violation of this policy will result in a penalty. If found in violation of
the academic dishonesty policy, students may be subject to two types of
penalties. The instructor administers an academic (grade) penalty, and the
student may also enter the Institute judicial process and be subject to such
additional sanctions as: warning, probation, suspension, expulsion, and
alternative actions as defined in the current Handbook of Student Rights and
Responsibilities. If you have any question concerning this policy before
submitting an assignment, please ask for clarification.
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What is expected
• Attend class, complete assignments (esp.
reading)
• Participate
• Ask questions
• Work both individually and in a group
• Work constructively in group and class sessions
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Questions so far?
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Introduction to
Geographic Information Systems
What is a GIS?
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GIS as a domain of science and
technology
Geography
Landscape
Architecture
Geographic Information Science & Technology
Various
Application
Domains
Philosophy
Psychology
Mathematics
They worked on
Statistics
Geographic
Information
Science (land
‘positions’
Application of
GI Science &
Technology
survey)
before
entering politics
Geospatial
Technology
Computer
Science
Information
From
GI System to
George Washington
Thomas JeffersonScience &
Technology
GI Science & Technology
Engineering
Abraham Lincoln
(DiBiase et al. 2006)
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Geographic Information Science
• Hmm, a broad
S
– From GISystems to GIScience
– GIScience: the science behind GISystems technology
• considers fundamental questions raised by the use of systems
and technologies
• is the science needed to keep technology at the cutting edge
Courtesy: http://www.ncgia.ucsb.edu/giscc/units/u002/u002.html
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The purpose of GIS
GIS stands for ‘Geographical Information System’.
A GIS consists of:
• Digital Data –– the geographical information that you will
view andanalyse using computer hardware and software.
• Computer Hardware –– computers used for storing data,
displaying graphics and processing data.
• Computer Software –– computer programs that run on
the computer hardware and allow you to work with digital
data. A software program that forms part of the GIS is
called a GIS Application.
Image: qgis.org
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The purpose of GIS
Image: qgis.org
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The purpose of GIS
• A biologist might be
interested to determine
how widespread the
invasive Asian clam in
Lake George was, and to
develop and implement an
eradication plan.
Asian clam identified in Lake George, NY
Image courtesy of lakegeorge.com
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The purpose of GIS
• A geological engineer
might want to identify the
best localities for
constructing buildings in an
area with regular
earthquakes by looking at
rock formation
characteristics.
Rock outcrop, North San Francisco
Image courtesy of Pascal Calarco
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The purpose of GIS
• A forest manager might
want to optimize timber
production using data on
soil and current tree stand
distributions, in the
presence of a number of
operational constraints,
such as the requirement to
preserve tree diversity.
Timber production
Image courtesy of futureforest.eu
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The purpose of GIS
• Brainstorm: What are some spatial questions YOU
would like answered? (not just science now)
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Spatial data and geoinformation
• Data are representations that can be operated upon by a
computer.
• Spatial data are data that contain positional values.
• Geospatial data are spatial data that are georeferenced.
• Metadata are data about data
(Who/what/when/where/why)
• Information is the meaning of data as interpreted by
human beings.
• Geoinformation is information that involves interpretation of
spatial data.
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Spatial data and geoinformation
• Data, Information, Knowledge, Wisdom (DIKW)
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The real world
and representations of it
• When dealing with data and information we are usually
trying to represent some part of the real world as it is, as it
was, or perhaps as we think it will be.
– We say ‘some part’ because the real world cannot be represented
completely.
• We use a computer representation of some part of the real
world to enter and store data, analyze the data and
transfer results to humans or to other systems.
Image courtesy of NOAA
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Modeling
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A representation of some part of the real world can be considered a model of
that part.
– This allows us to study the model instead of the real world.
Models come in many different flavors.
– Maps
– Databases
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Most maps and databases can be considered static models.
Dynamic models or process models address changes that have taken place,
are taking place and may take place.
One fundamental challenge in many uses of GIS is that of understanding
phenomena that have (a) a geographic dimension, and (b) a temporal
dimension. Spatio-temporal = be of/in space and time
“Everything that happens, happens somewhere in
space and time. ”
-- Michael Wegener (University of Dortmund)
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Maps
• Models of the real world are often visualized in maps.
• Cartography: science and art of map making
Two major kinds of maps:
• Static Maps
• Dynamic (Interactive) Maps
Static Maps
• Paper, PDF, TIFF, jpeg
• A static map is always a graphic representation at a certain
level of detail. (smaller the scale, the less detail the map can show).
Increasing map scale
Images made with Google Maps
• A static map is always a single snapshot in time.
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Static Maps
More examples of maps
Images courtesy of rpi.edu
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Static Maps
More examples of maps
Images courtesy of frontierspatial.com
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Static Spatio-Temporal Maps
Projected shifts
in forest types
Image source:
http://nca2009.globalchange.gov/
projected-shifts-forest-types
The maps show current and projected forest types. Major changes are projected
for many regions. For example, in the Northeast, under a mid-range warming
scenario, the currently dominant maple-beech-birch forest type is projected to be
completely displaced by other forest types in a warmer future.
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Static Spatio-Temporal Maps
Drought’s Footprint (1930 to present)
Image source: National Climatic Data Center, NOAA
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Dynamic Maps
• URL, on the web
• A dynamic map can present graphic representations at
multiple spatial scales, with varying degrees of detail.
Increasing map scale
Images made with GOOGLE
MAPS!
• Dynamic maps can incorporate time.
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Dynamic Maps
http://poncamap.sig-gis.com/
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Dynamic Maps
http://adkwebmap.com/hamletViz.php
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Dynamic Spatio-temporal Maps
http://roadtolarissa.com/meteors/
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(Dynamic) Spatio-temporal Maps
w/real-time data
http://hint.fm/wind/
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Dynamic Spatio-temporal Maps
http://roadtolarissa.com/twisters/
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Databases
• A database is a repository for storing
large amounts of data.
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It allows concurrent use.
It supports storage optimization.
It supports data integrity.
It has a query facility.
It offers query optimization.
• (Most) modern database systems
organize the stored data in tabular
format.
• A database may have many tables,
and each table may have many
columns (attributes) and rows
(records).
Image courtesy of
MapInfo User Guide
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Spatial databases
• Spatial databases are a specific type of database.
– Besides traditional administrative data, they can store
representations of real world geographic phenomena for use in a
GIS.
– A spatial database, also called a geodatabase, focuses on
concurrency, storage, integrity, and querying of spatial data.
– A GIS focuses on operating on spatial data with a ‘deep
understanding’ of geographic space.
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Spatial databases
• Geographic phenomena have
various relationships with each other
and possess spatial, temporal, and
thematic attributes.
• For data management purposes,
phenomena are classified into
thematic data layers.
• Spatial analysis is the generic term
for all manipulations of spatial data
carried out to improve one’s
understanding of the geographic
phenomena that the data represent.
Image courtesy of Jonathan Campbell and Michael Shin
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Spatial data and geoinformation
• In GIS, one must be mindful of the QUALITY of your data!
– Even source data that have been subject to strict quality control,
errors are introduced when these data are input to a GIS.
– A GIS database normally contains data from different sources of
varying quality.
– Most GIS analysis operations will themselves introduce errors.
– Uncertainty in decision-making depends upon quality of base data
and derived information.
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Spatial data and geoinformation
Comparison of
seven available
digital databases
of the streets in
part of Goleta,
CA, USA
(Goodchild 2011)
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For Next Monday
Monday Lecture: GIS I: Projections & vector data
Readings: (links at: http://tw.rpi.edu/web/Courses/GIScience/2014)
• Maps (Wikipedia)
• GIS overview (QGIS website)
• Spatial References (QGIS website)
• Vector Data (QGIS website)
Install QGIS on your laptop! (qgis.org)
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