Intro to GIS

GIS

Geographic Information Systems

What is one kind of GIS that is commonly used?

Google Earth

When was the first use of Spatial Analysis?

1800s London Cholera Outbreak

Who was the first person to use Spatial Analysis in London to help track Cholera outbreaks?

Dr. John Snow

What are maps made up of?

Layers

Layers

Parts of a map that correspond to a single feature type

What are two examples of vector data?

Points, Lines

What does raster data represent?

Surfaces

UTM

Universal Transverse Mercator

How are UTM boundaries measured?

Meters

How are UTM Zone Coordinates found?

Northing and Easting

Northing

Distance north of equator

Easting

Distance east from zone barrier

What is an important consideration when inputting data in a GIS system?

All data is same coordinate system

A map projection can measure

size, shape, distance, direction

Why can not all measurements be shown at once on one map projection?

The earth is round

What are three major projection families?

Cylinders, planes, cones

What kind of projection is a mercator map?

Cylinder

What kind of projections can an equal area map be?

Plane or cone

What kind of projection is a polyconic map?

Cone

What is one good resource for GIS Data

World WGS 84

What makes a good map?

Purpose, title, scale bar, legend, north arrow

Raster

model of grid-like cells arranged in rows and columns composed of single or multiple bands 

Attribute

Values that provide information about a feature or data point in a GIS.

Metadata

Contextual information about a dataset, map, or app.

What can metadata include?

date, time, origin, availability, distribution information

Spatial Analysis

using spatial data to answer a question or gain useful knowledge

Spatial Reference

rules to clarify the coordinate system and spatial properties used in a data set

What is spatial reference used for?

to provide common rules for measuring and representing geographic features from different sources

Common cylinder based map

Mercator Map

Plane or cone based map used for navigation

Equal Area Map

Cone Based map shaped like a peach

Polyconic Map

Datum

Method used to glue a grid onto a geoid

NAD27

North American Datum of 1927

WGS84

World Geodetic System

NAD83

North American Datum of 1983

DMS

Degrees Minutes Seconds

DD

Decimal Degrees

What is the difference between geographic and projected coordinate systems?

GCS defines where, PCS defines how to put it on a flat surface

Geoid

The shape of earth assuming no waves or tides in the ocean