Transcript Introductory Lecture

GIT461/561 GIS:
Environmental Science
Introductory Lecture
By David T. Allison, Ph.D.
Lecture 1
► Lecture
1 Topics
 Introduction to GIS lab equipment and protocols
 Basics of Operating Systems and File
Management
 Basics of Map Projections and how they work in
ArcGIS
 Sources of Digital Base Maps
 Starting the Yosemite Valley Project
GIS Laboratory Usage
► Rules
for Using the GIS Lab (LSCB 137)
 The lab is for use only by students taking GIS-based
courses within the Dept. of Earth Sciences
 Do not use the workstations for tasks other than GIS
course work (no checking e-mail, music downloading,
printing term papers, etc.)
 No food or drink is allowed in the lab
 Do not give out the lab door combo to friends, family,
etc.
 Try not to touch the screen with your fingers, instead
use the eraser end of a pencil
 Don’t leave book bags, purses or other gear in the lab
unattended
GIS Lab Hardware
► LSCB
333 - 24 “Thin Client” workstations:
 Intel Xeon 2-core CPU 2.4 Ghz
 2.0 Gb RAM
 40 Gb HD
► HP
5500 Color DesignJet Plotter (60 inches
x 150 feet).
► HP LaserJet 200 color laser printer.
► 36 inch wide 600 dpi scanner (146 LSCB).
► LSCB 146 – 12 workstations.
GIS Lab Workstation Software
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Each workstation is a virtual client running Windows 7 from
a server.
Workstation Application Software:
 ArcGIS 10.2
 Microsoft Office Professional 2012
►Excel
►Word
►Access
►PowerPoint
Google Chrome
Google Drive
Client/Server Model
Advantages/Disadvantages
► Advantages
 Server “serves up” the same OS and Application
environment to all workstations.
 Cheaper to maintain and purchase.
 Upgrading software: one-step process.
► Disadvantages
 Users (students) cannot store work on hard
drive because it is initialized to a standard state
on every re-boot.
 Performance is limited by server bandwidth.
Operating Systems
► Software
interface between hardware and
application software (i.e. ArcGIS).
► OS systems: Windows, MacOS, Unix, Linux,
Android
► Currently ArcGIS desktop software runs on
Windows, however, file servers that make
ArcGIS maps available on the web are likely
to run Linux with Apache server.
Windows 7 File Management
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Most problems in ArcGIS assignments stem from poor file
management skills.
Do’s and Don’ts:
 Do learn Win7 file explorer application.
 Don’t copy files/folders to the desktop.
 Do learn how to copy entire folders from one disk to
another in one step.
 Don’t save ArcGIS projects to a flash drive from within
the application- exit first and use file explorer to copy
folder to flash drive.
 Do learn how Google Drive/Dropbox work so that your
work is stored safely in the “cloud”.
Windows 7 Desktop with ArcGIS
Installed
ArcGIS 10.x Components
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ArcMap Application: basic map-making application for
ArcGIS.
ArcCatalog Application: file management and file creation
application for ArcGIS.
ArcScene: application for manipulating and presenting 3D
perspectives of 3D data (ex. “fly-through” videos).
Spatial Analyst extension: manages spatially related data
relationships (ex. produces a contour map from
topographic survey data).
3D Analyst extension: manages the geometry of threedimensional data (ex. subtracts a lower contact from an
upper contact to produce an isolith map).
GIS/Map Terminology
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DRG: digital raster graphic. A scanned topo or aerial map
that is georeferenced.
DEM: digital elevation model. A rectangular array of
elevation values. Usually interpolated from survey data.
GCS: geographic coordinate system. Locations are
measured with latitude and longitude.
UTM: a world-wide projected coordinate system using
meter units.
SPCS: State Plane coordinate system- a U.S. state specific
projected coordinate system using feet units.
World File: a text file containing the mathematical
information needed to project a raster image into a
Projected coordinate system.
Map Projections
► Map
projection: used to represent the
surface of Earth on a flat sheet of paper or
orthogonal coordinate system
► Map projections are subdivided into 2
categories:
 Equal Area: area is preserved but azimuth
angles are distorted (Transverse Mercator)
 Equal Angle: azimuth angles are preserved but
area is not (Mercator)
Map Projection Properties of
ArcMap
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ArcMap projects added feature classes (layers) on the fly
based on the feature’s coordinate system and the project
file coordinate system.
Raster images will be “rubber-sheeted” to fit the project
file coordinate system.
If no coordinate system is selected for a project the first
layer added to the project will set the coordinate system
for the project file.
If a layer does not have an assigned coordinate system
ArcMap assumes that the coordinates are in the current
project system.
GIS Coordinate Systems
► GIS
systems handle map projections in 2
fundamental ways:
 Geographic coordinates: the longitude and latitude
values are retained in the project and projected to the
screen or hard copy in a way decided by the software.
 Projected coordinates: longitude and latitude values are
used as defined by published systems (UTM, SPCS,
etc.).
 GIS systems can mix different systems together as long
as the raw data is stored as coordinates, not as a raster
file.
Projection Systematics in ArcMap
Topo Raster
UTM NAD27
Excel GPS
coordinates
GCS
ArcMap
Project
UTM NAD83
Plotted Map
Parcel
Boundary
SPCS
All layers are seamlessly
projected into UTM
NAD83 coordinates
Raster Data
Raster data is often used with GIS projects because they
provide critical base map information (topographic base,
DEM, Orthophoto, etc.)
► To be used with GIS a raster file (.TIF, .JPG, .BMP, etc.)
must have a “world file” that defines how the bit map fits
into a projected coordinate system.
► A common type of raster that we will be using often is a
digital raster graphic (DRG) USGS topographic quadrangle
that uses the UTM coordinate system
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Units: meters
Map datum: NAD27 or NAD83
File format: TIFF
World file: TFW or TFWX
Raster World File
► Contains
projection transformation
information that places raster in coordinate
system (.tfw or .tfwx file):
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3.81 (x dimension of pixel)
0.00 (rotation from x axis)
0.00 (rotation from y axis)
-3.81 (y dimension of pixel)
592649.993 3652430.161 (x,y coordinates of
upper left corner of raster)
Raster Map Projection
• UTM projection coordinates
• Geographic coordinates
Yosemite Project
► Georeference
topographic base maps – i.e.
create world files.
► Digitize polygon, polyline (arc), point, and
text annotation data.
► Symbolize geometry
► Calculate quantities important to project
goals.
► Plot final maps.