Basics of GIS

Earth Sciences & Map Library Workshop Series

Phil White

Earth Sciences & Environment Librarian

http://bit.ly/CULibBasicGIS

Earth Sciences & Map Library Workshop Series

Workshop Agenda:

Part 1: What is GIS & what can I do with it?

  • Slides/discussion

  • Hands on QGIS

Part 2: Historical GIS

  • Slides/discussion
  • Exemplars
  • Hands on QGIS

GIS Basics

Earth Sciences & Map Library Workshop Series

GIS Basics

Download Workshop Data!

libguides.colorado.edu/GIS

Earth Sciences & Map Library Workshop Series

What is GIS?

GIS Basics

GIS is a tool for storing, organizing, manipulating, analyzing, and visualizing data.

Earth Sciences & Map Library Workshop Series

GIS Basics

Not just any data...

Spatial Data!

Earth Sciences & Map Library Workshop Series

GIS Basics

5 Things:

Points

Lines

Polygons

Cells

Associated Attributes

Earth Sciences & Map Library Workshop Series

GIS Basics

Cells (AKA Raster Data)

mapschool.io

Earth Sciences & Map Library Workshop Series

GIS Basics

More than just cells...

Attributes!

DEM

(Digital Elevation Model)

 

White Cell = 2402.89 m

 

Black Cell = 1735.06 m

Earth Sciences & Map Library Workshop Series

GIS Basics

Raster Formats

  • Usually geoTIFF
  • Also ArcGRID, jpeg2000

Earth Sciences & Map Library Workshop Series

GIS Basics

Points, Lines, Polygons (AKA Vector Data)

Earth Sciences & Map Library Workshop Series

GIS Basics

mapschool.io

Earth Sciences & Map Library Workshop Series

GIS Basics

Earth Sciences & Map Library Workshop Series

GIS Basics

Earth Sciences & Map Library Workshop Series

GIS Basics

Attributes

Earth Sciences & Map Library Workshop Series

GIS Basics

Vector Formats:

  • Usually shapefile (.shp)

 

Also:

  • Geodatabase (.gdb)
  • kml/kmz
  • Spatialite (SQL)
  • GeoJson

Earth Sciences & Map Library Workshop Series

GIS Basics

When adding data to a GIS, we often refer to them as "layers."

Earth Sciences & Map Library Workshop Series

GIS Basics

Putting stuff on a map is more complicated than it seems.

Earth Sciences & Map Library Workshop Series

GIS Basics

Earth Sciences & Map Library Workshop Series

GIS Basics

mapschool.io

Because Earth's shape is irregular and changing, assigning locations is imperfect.

We use imaginary reference systems to approximate.

We tend to call this a "datum."

Earth Sciences & Map Library Workshop Series

GIS Basics

Earth Sciences & Map Library Workshop Series

GIS Basics

Common Datums: NAD83, WGS84

In GIS, we often use the term

"datum,"

"coordinate reference system,"

and

"geographic coordinate system" interchangeably

Latitude

 

Longitude

 

X

Y

Earth Sciences & Map Library Workshop Series

GIS Basics

GIS data usually has a coordinate system built right into it.

GIS software will take that information and place your data at the right spot automatically...

...usually.

Earth Sciences & Map Library Workshop Series

GIS Basics

Projections

Earth Sciences & Map Library Workshop Series

GIS Basics

mapschool.io

Distortion...

...is inherent to map projections.

Shape, Area, Distance, & Direction

Earth Sciences & Map Library Workshop Series

GIS Basics

Mercator

Good for direction

Bad for Shape

(Hello Greenland!)

Earth Sciences & Map Library Workshop Series

GIS Basics

Google Maps

Gall-Peters

Earth Sciences & Map Library Workshop Series

GIS Basics

Wikimedia

Scale

Large Scale

Small Scale

1:75,000,000

1:25,000

Earth Sciences & Map Library Workshop Series

GIS Basics

Enough blathering!

 

How do I use GIS? 

Earth Sciences & Map Library Workshop Series

GIS Basics

Take some data....

...do some stuff to it...

...communicate new info.

Earth Sciences & Map Library Workshop Series

GIS Basics

Stuff we do:

Symbolize

Aggregate

Interpolate

Overlay

Measure

Earth Sciences & Map Library Workshop Series

GIS Basics

Geocode

Georeference

Symbolization

Earth Sciences & Map Library Workshop Series

GIS Basics

mapschool.io

Earth Sciences & Map Library Workshop Series

GIS Basics

Wikimedia

Earth Sciences & Map Library Workshop Series

GIS Basics

Wikimedia

Those are called "Choropleth Maps."

Earth Sciences & Map Library Workshop Series

GIS Basics

Earth Sciences & Map Library Workshop Series

GIS Basics

Overlay

Jordan Wirfs-Brock

Earth Sciences & Map Library Workshop Series

GIS Basics

Overlay

Earth Sciences & Map Library Workshop Series

GIS Basics

Aggregate

http://demographics.virginia.edu/DotMap/

Earth Sciences & Map Library Workshop Series

GIS Basics

Interpolate

mapschool.io

Earth Sciences & Map Library Workshop Series

GIS Basics

Measuring

Earth Sciences & Map Library Workshop Series

GIS Basics

Georeference

David Rumsey Center

Earth Sciences & Map Library Workshop Series

GIS Basics

Geocoding

Earth Sciences & Map Library Workshop Series

Intro to ArcMap

Resources available to you:

Earth Sciences & Map Library Workshop Series

GIS Basics

</part 1>

Earth Sciences & Map Library Workshop Series

GIS Basics

<part 2!>

Earth Sciences & Map Library Workshop Series

Historical GIS

Historical GIS:

Use of GIS to study the history of a place... 

Or

an event related to place...

Or

well, many things!

Earth Sciences & Map Library Workshop Series

Historical GIS

The Main Challenges:

Turning historical information into geospatial data

  • Georeferencing scanned maps
  • Vectorizing/digitizing
  • Assigning locations to information culled from historical documents (very time consuming)

Goal: Getting new information out of the GIS 

  • Visualization
  • Spatial Analysis 
  • Learn from your data and communicate!

Earth Sciences & Map Library Workshop Series

Historical GIS

Exemplars

 

Mapping Inequality

Bomb Sight

The Roman World

Earth Sciences & Map Library Workshop Series

Historical GIS

Let's get our hands dirty.

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