Transcript - Rensselaer Polytechnic Institute

GIS in the Sciences
ERTH 4750 (38031)
Introduction to
Geographic Information Systems
Xiaogang (Marshall) Ma
School of Science
Rensselaer Polytechnic Institute
Tuesday, January 22, 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
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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
• Name, major, year
• Interests, goals, outcomes
• Have you completed any *suggested*
prerequisites:
– Geography, cartography
– Other spatial analysis
– Mathematics background
• Questions
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Course Outline (tentative)
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Week 1 (Jan. 22/25): Introduction to GIS
Week 2 (Jan. 29/Feb. 1): Geographic information and spatial data types
Week 3 (Feb. 5/8): Spatial referencing
Week 4 (Feb 12/15): Geostatistical computing
Week 5 (Feb. 19/22): Exploring and visualizing spatial data
Week 6 (Feb. 26/Mar. 1): Modeling spatial structure from point samples
Week 7 (Mar. 5/8): Spatial prediction from point samples (Part 1)
Week 8 (Mar. 12/15: no classes - spring break)
Week 9 (Mar. 19/22): Spatial prediction from point samples (Part 2)
Week 10 (Mar. 26/29): Assessing the quality of spatial predictions
Week 11 (Apr. 2/5): Interfacing R spatial statistics with GIS
Week 12 (Apr. 9/12: no class - Grand Marshall week)
Week 13 (Apr. 16/19): Efficient and effective result presentation with GIS
Week 14 (Apr. 23/26): Tuesday: Guest Lecture, Friday: lab
Week 15 (Apr. 30): Tuesday: Short final project presentations
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Course Outline (tentative)
•
•
•
•
•
•
•
•
•
•
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Week 1 (Jan. 22/25): Introduction to GIS
Week 2 (Jan. 29/Feb. 1): Geographic information and spatial data types
Week 3 (Feb. 5/8): Spatial referencing
Week 4 (Feb 12/15): Geostatistical computing
Week 5 (Feb. 19/22): Exploring and visualizing spatial data
Week 6 (Feb. 26/Mar. 1): Modeling spatial structure from point samples
Week 7 (Mar. 5/8): Spatial prediction from point samples (Part 1)
Week 8 (Mar. 12/15: no classes - spring break)
Week 9 (Mar. 19/22): Spatial prediction from point samples (Part 2)
Week 10 (Mar. 26/29): Assessing the quality of spatial predictions
Week 11 (Apr. 2/5): Interfacing R spatial statistics with GIS
Week 12 (Apr. 9/12: no class - Grand Marshall week)
Week 13 (Apr. 16/19): Efficient and effective result presentation with GIS
Week 14 (Apr. 23/26): Tuesday: Guest Lecture, Friday: lab
Week 15 (Apr. 30): Tuesday: Short final project presentations
MapInfo
R
Mashup
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Logistics
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Class: ERTH 4750
Hours: 4pm-5:50pm Tuesday, Friday
Location: JRSC 2C25
Instructor: Xiaogang (Marshall) Ma – [email protected]
Contact hours: Thursdays 1pm-2pm (or by appointment)
Contact location: JRSC 1W01 or Winslow 2120
TA: Anastasia Rodzianko, [email protected]
Web: http://tw.rpi.edu/web/Courses/GIScience/2013
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Schedule, syllabus, reading, assignments, etc.
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Assessment and Assignments
• Via written assignments with specific percentage of grade
allocation provided with each assignment
• Via individual oral presentations with specific percentage
of grade allocation provided
• Via group presentations – depending on class size
• Via participation in class (not to exceed 10% of total) – this
works by ‘losing’ points by not participating
• 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
• You will progress from individual work to group work
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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, reference frames, multivariate analysis,
correlation analysis, regression, interpolation,
extrapolation, and kriging.
• To gain experience in an end-to-end GIS application via a
term project.
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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
•
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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Skills needed
• Geography?
– Nah, we’ll cover that
• Literacy with computers that can load and run the
relevant applications
• Ability to access Internet and retrieve or acquire
data
• Presentation of assignments
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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
Now let’s start
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Contents
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1 The purpose of GIS
2 The real world and representations of it
3 GIS as a domain of science and technology
4 Seven levels of GIS competence
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1 The purpose of GIS
• A few example scenarios
• An urban planner might like
to find out about the urban
fringe growth in her/his city,
and quantify the population
growth that some suburbs
are witnessing. S/he might
also like to understand why
it is these suburbs and not
others.
Urban fringe, Waitara, New Zealand
Image courtesy of Quentin Christie
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1 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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1 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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1 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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1 The purpose of GIS
• Various professionals work with data that relates to space,
typically involving positional data.
• Positional data determines where things are, or perhaps
where they were or will be.
George Washington
Thomas Jefferson
Abraham Lincoln
They worked on ‘positions’ (land survey) before entering politics
Images courtesy of wikipedia.org
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1 The purpose of GIS
• More precisely, those professionals’ questions are related
to geographic space, which have positional data relative to
the Earth’s surface (georeferenced data).
– There are also positional data of a non-geographic nature.
• A Geographic Information System (GIS) is a computerized
system that helps in maintaining and displaying data about
geographic space.
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1.1 Some fundamental observations
• Our world is constantly changing, and not all changes are
for the better.
– Natural causes: e.g., volcanic eruptions
– Human causes: e.g., land use changes
– Mix / Unclear causes: e.g., El Niño / La Niña events
Grimsvotn volcano, May 21, 2011
U.S. Drought of 2012
Image courtesy of AP / Jon Gustafsson
Image courtesy of The NY Times / Mashid Mohadjerin
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1.1 Some fundamental observations
• We, humans, want to understand what is going on in our
world, and to take action(s).
• The fundamental problem 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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1.1 Some fundamental observations
Drought’s Footprint (1930 to present)
Image source: National Climatic Data Center, NOAA
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1.1 Some fundamental observations
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 midrange 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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1.2 Definition of GIS
• We may distinguish three important phases of working with
georeferenced data:
– Data preparation and entry
– Data analysis
– Data presentation
• The three phases may be repeated a number of times
before we are satisfied with the results.
• We can define a GIS as a computerized system that
facilitates the phases of data entry, data analysis and data
presentation especially in cases when we are dealing with
georeferenced data.
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1.3 Spatial data and geoinformation
• Data are representations that can be operated upon by a
computer.
• Metadata are data about data.
• Spatial data are data that contain positional values.
• Geospatial data are spatial data that are georeferenced.
– In the context of GIS, spatial data and geospatial data are regarded
as synonyms of georeferenced data.
• Information is the meaning of data as interpreted by
human beings.
• Geoinformation is information that involves interpretation of
spatial data.
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1.3 Spatial data and geoinformation
Experience
Data
Creation
Gathering
Image courtesy of Peter Fox
Information
Presentation
Organization
Knowledge
Integration
Conversation
Context
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1.3 Spatial data and geoinformation
• In GIS, a wider view of QUALITY is important for several
reasons:
– Even source data 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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1.3 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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2 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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2.1 Modeling
• 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
– ……
• 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.
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2.1 Modeling
Pangaea: a supercontinent that
existed about 300 million years ago
Static model: map of Pangaea
with present continents outlined
Image courtesy of Wikipedia
Dynamic model: break-up of
Pangaea and formation of
modern continents
Image courtesy of USGS
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2.2 Maps
• The best known models of the real world are maps.
• A map is always a graphic representation at a certain level
of detail.
– The smaller the scale, the less detail a map can show.
• Cartography: science and art of map making
Images made with Google Maps
Image © Bil Keane.
Courtesy of familycircus.com
Map scale increasing
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2.2 Maps
More examples of maps
Images courtesy of rpi.edu
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2.3 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.
• Modern database systems organize the stored data in
tabular format.
Image courtesy of
MapInfo User Guide
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2.3 Databases
• A database may have many tables, and each table may
have many columns (attributes) and rows (records).
• During database design, it is determined which tables will
be present and which columns each table will have.
• The result of a completed database design is known as the
database schema.
• To define the database schema, we use a language,
commonly known as a data model.
• The definition of a model is called data modeling.
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2.4 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.
• A spatial database is used under the assumption that the
relevant spatial phenomena occur in a two- or threedimensional Euclidean space.
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2.4 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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3 GIS as a domain of science and
technology
Geography
Landscape
Architecture
Geographic Information Science & Technology
Various
Application
Domains
Philosophy
Psychology
Mathematics
Geographic
Information
Science
Statistics
Application of
GI Science &
Technology
Geospatial
Technology
Computer
Science
From GI System to
GI Science & Technology
Engineering
Information
Science &
Technology
(DiBiase et al. 2006)
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3.1 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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3.2 Geospatial technology
• Geospatial technology / Geomatics
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Land surveying
Remote sensing
Cartography
Geographic information systems (GIS)
Global navigation satellite systems (GPS, GLONASS,
Galileo, Compass)
– Photogrammetry
– Geography
–…
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3.2 Geospatial technology
• Global Positioning System (GPS)
– a system of Earth-orbiting satellites transmitting
precisely timed signals
• a similar system deployed by the Russian Federation is called
GLONASS (global navigation satellite system)
• and other systems by EU, China, India, etc.
– signals are received by a special electronic device
• the smallest versions are hand-held and even smaller
– provides direct measurement of position on the Earth's
surface
– location is expressed in latitude/longitude or other
standard system
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3.2 Geospatial technology
• GPS
Image source: Wikipedia
Image source: Wikipedia
Image from WWW
Image source: AP
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3.2 Geospatial technology
• Remote Sensing (RS)
– use of Earth orbiting satellites to capture information
about the surface and atmosphere below
– satellites vary depending on how much detail can be
seen, what parts of the electromagnetic spectrum are
sensed
– signals transmitted to Earth receiving stations where
they are transformed for dissemination as digital images
Courtesy: http://www.ncgia.ucsb.edu/giscc/units/u002/u002.html
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3.2 Geospatial technology
• Two main types of RS
– Passive RS: detect natural radiation (e.g., sunlight) that
is emitted or reflected by the object or surrounding
areas
– Active RS: emits energy (e.g., laser light) in order to
scan objects and areas whereupon a sensor then
detects and measures the radiation that is reflected or
backscattered from the target
Images from:
http://www.rsgisrs.com/rs_types.htm48
Night lights of Australia as observed by the Visible Infrared Imaging Radiometer
Suite (VIIRS) on the Suomi NPP satellite in April and October 2012
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Fires
More information: http://earthobservatory.nasa.gov/IOTD/view.php?id=80030&src=fb
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3.2 Geospatial technology
• GISystems
– a computerized system that facilitates the entry,
analysis, and presentation of georeferenced data
• GPS and RS are primary data sources for GIS
Try these:
http://www.flightradar24.com/
http://shuttles.rpi.edu/
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4 Seven levels of GIS competence
• Levels of GIS competence in ascending order:
1.
2.
3.
4.
5.
6.
7.
Public awareness of GIS and its uses;
Basic spatial and computer understanding;
Routine use of basic GIS software;
Higher-level modeling applications of GIS;
Design and development of GIS applications;
Design of geographic information systems; and
GIS research and development.
(DiBiase et al. 2006; Marble 1997)
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Reading for this week
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Map
GPS
Remote Sensing
MapInfo User Guide and other docs
See links to them at:
http://tw.rpi.edu/web/Courses/GIScience/2013
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Next classes
• Friday class:
– install and work with MapInfo / Map Basic
– RPI has an on-site license of MapInfo
– http://www.rpi.edu/dept/arc/web/software/sw_available.html
• Start working with it, ask questions…
• In preparation:
– Next Tuesday: Geographic information and spatial data
types
– Also, check course webpage for additional resources:
– http://tw.rpi.edu/web/Courses/GIScience/2013
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