Introduction to GIS and ArcGIS Online

Joy Suh Geospatial Resources Librarian

(hsuh1@gmu.edu)

Fall 2020

What will cover today? • Geospatial Data

• Basic Concepts of GIS and its

applications

• Data Resources

• Software Access & Training

• Hands-On with ArcGIS Online

Geographical Information Systems (GIS)

A computer-based data management systems to help

create, visualize, store, manipulate and analyze

information that is tied to a geospatial data (location

data).

Geospatial Data

• “Information that identifies the location of

geographic features and characteristics of natural

or man-made objects on the earth”

So called “geographically reference data” or

longitude and latitude (XY), or spatial data

Ways to Collect Geodata • Address Data (in Spreadsheet format)

• XY Data (in Spreadsheet format)

• Print map (scanned Image of a map) (JPEG) Georeferencing

• Digitizing using GIS tool

• Get GIS Data available from authorized sources or on Web

See more: http://infoguides.gmu.edu/geospatial

Tabular Examples (.csv .xlsx .txt)

Geographical Unit is a observation unit

Which one is a geospatial dataset?

Two Types of Geospatial Data

Vector Data Raster Data

• Represent “Real Word

View” based on:

Point, Line and Polygon

• Data format: Shape file

(.shp)—Zip format

• Example: US Census

Tiger files

• Represent “Real World View” based on: Grid (Pixel)

• Data format: Digital Image File

(. geoTiff, tiff, jpg, etc)

• Example: USGS Digital

Elevation (DEM or DOQQ) & NGA’s Satellite Images, NOAA

“Feature Based Data”

Geospatial Data & Types • Point, Lines, Polygons, Grids—Typology data type

Vector Data (.shp) Raster Data (.geotiff)

How does GIS work?

Capability: Overlay Layers

Capabilities: Data Overlay

Create a new layer through overlay (with the same location and the same

coordinate system)

Example: Overlay different data formats and create a new layer.

11

Geographic Coordinates

• Latitude= North (+) or South (-) from 0 (Equator) to 90 at the N/S Poles

• Longitude = East (+) or West (-) from the Prime Meridian

3 Dimensions

Geographic Coordinates

X

Fairfax, VA Lat(Y)= 38.8505 Long(X)= -71.3032

Units= Degrees, Minutes, Second or Decimal Degrees.

• can convert between the two

2 Dimensions

Projections & Coordinate Systems

• Geographic Coordinate System (GCS) - Location on a sphere (latitude/longitude, 3 dimension)

• Datum (goes along with the GCS) - An estimate of Earth’s actual shape fit into a spheroid

(World Geodetic Survey (WGS) 83, NAD27(83)

• Projected Coordinate System - Location on a flat map from a defined 0,0 origin

See more at:

http://egsc.usgs.gov/isb/pubs/MapProjections/projections.html

10

Projection Continued

Data Alignment in GIS

Define a Coordinate and Use the same coordinate for Data Alignment (source: http://pro.arcgis.com/en/pro-app/tool-reference/editing/align-features.htm)

No Spatial Information

Spatial Information Spatial Reference needs to be defined in GIS

Benefits (Principles) of GIS • Visualize and interpret patterns and spatial

relationships

• Analyze spatial information and trend (Spatial

Analysis, Spatial Statistics, Network Analysis,

Space_Time Analysis, etc)

• Ask interactive spatial questions

• Predict future impact and create models

• Develop effective solutions

• Display and communicate spatial information

1

1

Source: http://mason.gmu.edu/~aaburiza/snowCholeraMap/ For 2015 GIS Day Demonstration @Mason : GIS and Health

Applications of GIS

• Academics—interdisciplinary (see library databases, search GIS)

• Federal (USGS), state, & Local Agencies

• Industry (www.esri.com>Solutions>Industries)

Specific examples:

• 2008 Presidential Election (Univ. of Stanford—social sciences)

• Mapping Inequality (Univ. of Richmond-Digital Humanities)

• Covid-19 dashboard (JHU, Health)

Finding Geospatial Data

Library Infoguides—Geospatial Data & GIS

http://infoguides.gmu.edu/geospatial/data

• Data.gov (US Federal Agency Data) • ArcGIS Hub (Organizations and US local

governments) • DIVA (Global) • Natural Earth (Global) • Geodata@Mason

19

Access to GIS Software &

Training

• Desktop—ArcGIS 10.7, QGIS (Open Source)

• Online: ArcGIS Online (AGOL),

• ArcMap ArcGIS Pro (Install via the Desktop version

or individual download from Online

• See more: infoguides.gmu.edu/geospatial/software

• See more:

https://infoguides.gmu.edu/geospatial/workshop

ArcGIS Online Basics • Access ArcGIS Online (arcgis.com) via the

organizational login

• Import your own data (csv and shape files)

• Search the ArcGIS Online and Add data (Living Atlas) available to your project.

• Choosing various symbols for mapping or visualization

• Overlay different layers to identify a possible relationship

• Share your created map

• Other applications: Web applications, Story Maps, Dashboard via ArcGIS Online

• More: See the details from the hands-on tutorial

Contact & URLs Joy Suh: hsuh1@gmu.edu

Infogudies.gmu.edu/geospatial

https://dsc.gmu.edu/gis/

21