GIS_Intro_March_2014

INTRODUCTION TO GIS
CONCEPTS & SOFTWARE
Building a Foundation of GIS KnowledgeDay 1

Key Learning Objectives
 To understand what a GIS is, including how
GIS is applied in a humanitarian context
 To gain a basic understanding of GIS
concepts and vocabulary.
 Get hands-on experience working with GIS
software to make basic maps, create, edit, &
integrate data from different sources.

Questions a GIS Can Help Answer
 Questions about space: where is an entity
located and what is its extent?
 Questions about attributes: what are the
characteristics of the entity located there?
 Questions about time: when were the
entity’s location, extent, or characteristics
measured? How has the entity changed
over time?

Questions a GIS is Not So Good for
 Why are the entities located there?
 Why do they have the kind of characteristics
that they have?
 Why have the characteristics changed over
time?
 GIS cannot provide clear-cut answers to
predictive questions right out of the box.

ArcGIS Desktop Components
ArcGIS Desktop product includes two applications:
ArcMap and ArcCatalog.
 ArcMap is the application you work with to
explore and analyze data and make maps.
 ArcCatalog is the application you work with to
manage data.

Exercise 1: Experiment with ArcGIS Interface
 Add data to ArcMap
 Locate Table of Contents, Toolbox, Catalog
 Move Toolbars
 Open & View Data in ArcCatalog
 Close ArcMap & ArcCatalog

Short Video About GIS Applications

Distinguishing Properties
of Geographic Data
□ Geographic data represent spatial locations and their associated
attributes measured at certain times
□ Geographic space is continuous
□ Geographic space is nearly spherical
□ Geographic data tend to be spatially dependent (things that are
close together tend to be more related than things that are far apart)
□ Geographic data are selective, generalized, and approximate
(the larger the area covered, the more generalized the data tends to be;
the smaller the area the more detail)
□ Getting it in Sucks (GIS) = The lion’s share of the cost of most GIS projects
is associated with the development of a suitable database)

Two Dominant GIS Formats
• VECTOR
• RASTER

Vector Data Model
The Vector Data is based on the assumption that the
earth's surface is composed of discrete objects such as
trees, rivers, and lakes.
Objects are sampled at intervals along the length of a road
or property parcel, for example.
The vector approach is well suited for mapping entities
with well defined edges, such as highways, pipelines, or
property parcels.

Shapefiles (.shp)
 ArcGIS uses shapefiles as the
smallest unit to create maps.
 Shapefiles are stored in a .shp format.
 Shapefiles contain information either
in form of points (e.g., villages), lines
(e.g., roads) or polygons (e.g., country
boundaries).

Shapefiles Continued….
 A single shapefile is actually composed of several computer
files. Depending on how the shapefile was created, there
may be up to seven separate files that comprise the
shapefile dataset.
 If you want to share a shapefile dataset, all of the
associated files must be transferred or the dataset will be
unusable.
 Shapefiles should not be moved from their original location
in the directory.
 Shapefile are a universal exchange format and used heavily
in GIS field

Raster Data Model
A raster data set is made up of a grid of square cells where all the cells
are the same size. (Pixels is another term for cells).
Each cell has a given value, depending on the type of dataset. In
general, these cells are squares and are organized in rows and
columns to form a rectangular dataset.
A raster strategy is a smart choice for representing data that lack
clear-cut boundaries, like terrain elevation, vegetation, and
precipitation.

Exercise 2: The Basics of ArcMap
□ Connect to folder
□ Add Data to ArcMap & Understand Layers
□ Understand what a Data Frame is
□ Explore data using appropriate tools (identify,
bookmarks, attribute tables)
□ Use a basic ArcMap skill set to build a map
□ Explore page & printer settings

Coordinate Systems
 The geographic coordinate system uses
spherical coordinates to identify points,
lines, or areas on the Earth’s surface.
 A projected coordinate system uses planar
coordinates to identify points, lines, or
areas on the Earth’s surface.

Prime Meridian
The prime meridian (green line) is the starting point
for longitude and has a value of 0.
The equator (red line) is the starting point for latitude
and has a value of 0. It runs midway between the
north and south poles, dividing the earth into
northern southern hemispheres.
Origin = (0,0)

Latitude-Northing
The distance north or south of the
equator of a point on the earth’s
surface.
Latitude ranges from 0 to 90 degrees at
the North pole to -90 degrees at the
South pole.

Longitude-Easting
Longitude is measured zero to 180° going
east or zero to -180° going west to the
International Date Line (IDL).

 Combined, these two measures
provide a location on the surface
of the Earth
Geographic Coordinate System

Geographic Coordinate System
 Position format
– Degree
• DDD.DDDDD – decimal degree
• DD MM SS.S – degree, minute, and second
Examples…
34.73459 (DDD.DDDDD)
34° 44’ 04.5” (DD MM SS.S)

Measuring Latitude & Longitude

Projected Coordinate Systems
 The surface of the earth is curved but maps are flat. To
convert feature locations from the spherical earth to a
flat map, the latitude and longitude coordinates from a
geographic coordinate system must be converted, or
projected, to planar coordinates.

What is a Map Projection?
 A map projection is a mathematical formula that we use
to convert data that are stored in spherical coordinates
(e.g., latitude and longitude) into plane coordinates.

Test Your Knowledge:
Let’s Play a Game!
https://www.e-education.psu.edu/natureofgeoinfo/c2_p11.html

Exercise 3: Coordinate System Practice
 Learn firsthand why it is important to
have data that is spatially reference.
 Learn how to look up a layer’s spatial
information.
 Learn how to define a coordinate system.

INTRODUCTION
TO CARTOGRAPHY
Making Maps & MorePart 1

Map Purpose & Audience
 Before you start making a map, it’s is
important to consider who your audience will
be and what their level of expertise is in the
subject matter you are mapping and in reading
maps.

Visual Hierarchy
Visual hierarchy adds depth to an image

Map Media
Map media may be classified into two major
types:
1.) Print (hard copy)
2.) Electronic media (soft copy)

Map Scale
 Map scale is the proportion between a
distance on a map and a corresponding
distance on the ground

Exercise 4: Setting a Map
Reference Scale
 Add layers
 Explore Layout View
 Learn how to set a reference scale
 Understand how setting a reference scale
affects features

Attribute Data
 A particular type, or category, of
information associated with a feature in a
GIS is called an attribute.
 For example, population can be an
attribute of a city, country, continent, and
other features.

Attribute Table
 Feature attributes are stored in an
attribute table. In an attribute table, each
feature is a record (row) and each
attribute is a column, or field. The
attributes for all the features in a layer
are stored in the same attribute table.

Exercise 4: Label Features
 Learn various ways to label features.
 Learn about masking labels.

Labeling Features
There are three ways to label features in ArcMap
1.) Use label tool on the draw toolbar
2.) Use data attribute fields to generate dynamic
labels
3.) create data frame annotation

INTRODUCTION
TO CARTOGRAPHY
Making Maps & MorePart 2

Exercise 1: Map Symbolization and
Layout
 Learn how to symbolize data
 Learn how to layout a map.
 Learn how to add various elements to a map,
such as scale bar, legend, north arrow.

Exercise 2: Make Your Own Map in Under 1
Hour
 Add at least 3 layers from data provided.
 Label all features, except roads.
 Use Masking for overlapping labels.
 Symbolize Data (edit font color, size, etc.)
 Classify Data (your area of map should be a different color than the
rest of the map).
 Insert Inset Map with extent rectangle.
 Layout Map (insert all map elements: title, scale bar, north arrow,
legend).
 Export for presentation.

Exercise 3: Data Creation & Editing
 Editor toolbar in ArcMap

Exercise 4: Mapping Refugee Camp
Infrastructure & Population Density

Exercise 1: Mapping Mae La
 Must have roads, rivers, polygon, houses
features
 Must have scale bar
 Must have north arrow
 Legend
 Layout
 Title
 Export
 Present

GIS_Intro_March_2014

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