GIS 1 (Shellito) Exam 1

What is GIS (definition)? What makes GIS different from other information systems?

GIS is computer-based mapping, analysis , and retrieval of location-based data.

What is "geospatial data" and what makes it unique?

Items (or data) that are tied to a specific real-world location

How is data created with GIS considered a model of the world?

How does the discrete view of the world treat real-world items when representing them in GIS?

They are represented as a series of objects with fixed boundaries (multiple lakes in a county, or roads).

What are the three geometric primitives of the vector data model (known as vector objects) and how are they used in GIS?

points (zero-dimensions), lines (one-dimension), and polygons (2-dimension); they are used by representing real-world data within GIS

What is an ellipsoid (Spheroid)?

An ellipsoid is a three-dimensional shape created from a two-dimensional ellipse; an ellipsoid is slightly larger at its center than at the poles.

What is a datum?

a reference surface of earth used for plotting locations across the globe

What are three common datums (NAD27, NAD83, WGS84) measuring and what are the differences between them?

1 - NAD27: developed for measurements of the US and North America;

2 - NAD83: developed by the National Geodetic Survey & Canadian agencies used for the US and the North American continent as a whole

3 - WGS84: the World Geodetic System of 1984 datum developed by the US Department of Defense & is used by the GPS for locating points worldwide on Earth's surface

How are coordinates found and read using the Geographic Coordinate System (GCS)?

a set of global latitude and longitude measurements used as a reference system for finding locations

What units of measurement are used in GCS?

degrees

What are map projections?

the translation of locations on a 3-D Earth to a 2-D surface

What distortions are associated with map projections (4)? Why do map projections have these distortions?

1 - Distance

2 - Area

3 - Shape

4 - Direction

Why are projected coordinate systems used in GIS?

The (PCS) allows you to make measurements in feet or meters rather than in degrees because it is a flat-grid system.

How are the Transverse Mercator and Lambert Conformal Conic map projections set up (and where are they the most accurate)?

Transverse Mercator - This projection is commonly used for data with a north-south orientation. Most accurate within 15 degrees of the central meridian.

Lambert Conformal Conic - Commonly used for data with an east-west orientation. Most accurate at middle-latitude locations (like the US).

What units are UTM and SPCS measured in?

1 - Universal Transverse Mercator (UTM) - meters

2 - State Plane Coordinate System (SPCS) - feet or meters

Why is it good practice to keep all GIS layers in the same projection, datum, and coordinate system?

To ensure that all of the GIS layers correctly line up inside of ArcGIS. If not, units could be incorrect, locations for real-world objects could be wrong, and the size and area of objects could be wrong.

What are the 3 levels of ArcGIS for Desktop and what are the differences between them?

Basic, Standard, & Advanced; the difference between them is functionality, i.e.- the number of functions available for each level.

In ArcMap's Catalog, how can you access a folder or drive not already listed in the catalog tree?

You must connect a folder to the catalog.

In ArcMap, what is a data frame and how is it used?

Data Frame - The section within ArcMap that contains and displays all data layers.

In ArcMap, what is the Table of Contents and how is it used with GIS data?

The section within ArcMap that shows all layers being used in a map document. You know, the section on the left.

In ArcMap, what are some common features available on the Tools toolbar?

Zoom In/Out, Pan, Full Extent, Hyperlink, Identify, Find, Select Features

In ArcMap, what are some common features available on the Standard toolbar?

New/Save/Open/Print Map, Copy/Paste/Delete Items, Undo/Redo, Add Data, Change Scale

What is a Map Document (.mxd file)?

A file that contains information about where all of the data layers used in a session are located, as well as their appearance and settings.

*What is really saved in the .mxd file when you save your work in ArcMap?

A pathway to get to the information stored rather than the actual information.

What is a Map Package (.mpk file)?

A single file that contains the map document PLUS all data layers used in the map document AND appearance

What are the differences between a Map Document and a Map Package?

Map Document is the "shell" of information where the Map Package is "the whole package" of information.

What is the difference between the "project" and "define projection" options in ArcGIS?

Project - A way of changing the coordinate system; for instance: NAD27 to NAD83

Define Projection - This is used when the data has NO defined coordinate system.

What is a database and what is a DBMS?

Database - one or more files that are structured in a way by a DBMS and accessed through it.

DBMS - Database Management System.

What do fields and records represent in a GIS attribute table?

Fields - the columns of an attribute table.

Records - the rows of an attribute table.

What are nominal, ordinal, interval, and ratio data?

Nominal - a type of data that is a unique identifier of some kind; differences between numbers are not significant

ex: Geological Map (different geological formations)

Ordinal - type of data that refers solely to a ranking of some kind

ex: Hazard map of Avalanches (1-10)

Interval - a type of numerical data in which the difference between numbers is significant, but there is no fixed non-arbitrary zero point associated with the data

ex: temperature map or pH values

Ratio - a type of numerical data in which the difference between numbers is significant, but there is a fixed non-arbitrary zero point associated with the data

ex: age, distance, weight, volume.

How are nominal, ordinal, interval, and ratio data represented in GIS with points, lines, and polygons (and what are some real-world mapping examples of each of these 12 concepts)?

What is a join? What is a key?

Join - a method of linking two (or more) tables together

Key - the field that two tables have to have in common with each other in order for the tables to be joined

How is a key used in joining two tables?

A "join" can only be performed between two tables only if they have a field in common (a key).

How can non-spatial data be accessed by performing a join?

You can join geo-spatial data together with non-spatial data as long as each table has a key (common field).

What restrictions are placed on joins?

Each common field (key) must be of the same type (both must be numbers, or text strings).

How does "Select By Attributes" operate as a database query?

You may build different queries to select certain data. You can create a new query, add to the query, remove from query, and select from current selection.... I don't know if any of this is important.

What gets selected as a result of a database query (or a Select By Attributes operation)?

The data that is selected is whatever data you set the parameters to select within the query. You know what I'm talkin' bout.

What is the format of an SQL query when used with a GIS attribute table?

SQL - Structured Query Language: works like a math function. Ex: Population > 10,000

How does a "simple query" operate (and what is the format of a simple query)?

A query that contains only one operator.

How does a "compound query" operate (and what is the format of a compound query)?

A query that contains more than one operator.

How do "AND," "OR," and "NOT" function in compound queries?

This does not need an answer.

What is cartography? What is a map?

Cartography - the art and science of creating and designing maps

Map - a representation of geographic data

What are the steps in the cartographic process?

no idea

What is the importance of map symbology as it relates to the three GIS vector objects?

This does not need an answer.

Why is map design important in GIS? How do color choices, typology, and placement and sizing of items impact the design of a map?

This does not need an answer. Well maybe it does... but bullshit this.

How is type best used on a map?

I don't even know how you put a type on a map to be honest.

How are colors best used on a map?

Colorfully.

What is geographic scale and how is it different from map scale?

the real-world size or extent of an area; map scale is a metric used to determine the relationship between measurements made on a map and their real-world equivalents

What is the difference between small scale and large scale maps?

Small Scale - a map with a lower value for its representative fraction; usually show a large amount of geographic area; (cities would be represented as dots).

Large Scale - a map with a higher value for its representative fraction; usually show a small amount of geographic area.

What is a representative fraction (RF) and how is it used to represent scale?

RF is a value indicating how many units of measurement in the real world are equivalent to how many of the same units of measurement on a map; An example would be (1:4000) = Large Scale & (1:250000) = Small Scale

How does the scale of the map affect what type of items can be represented on it using GIS?

It is important because it affects how much area can be displayed as well as the type of symbology that can be used.

*What is cartographic generalization?

the process of selecting and representing information of a map in a way that adapts to the scale of the display medium of the map.

What are a scale bar, north arrow, legend, and type and how are they used in making maps?

MAP ELEMENTS!

What is an ArcGIS layout?

A collection of map elements organized in the layout view in ArcMap, designed for printing maps. This is where you generally add the title, legend, scale bar, north arrow, & other stuff.

What is a map template?

A pre-made arrangement of items in a map layout

What is a thematic map (and what are some examples of a thematic map vs reference maps)?

a map that displays a particular theme or feature; some examples are: political maps, whether or not a state has a ban on a particular thing, or how many households in a state that have more than 2 children.

What is a choropleth map?

a type of thematic map in which data is displayed according to one of several different classifications

How do the following four types of data classification work and how do they represent data on a choropleth map:

1 - Natural Breaks

2 - Equal Interval

3 - Quantiles

4 - Standard Deviation

1 - Natural Breaks:

2 - Equal Intervals:

3 - Quantiles:

4 - Standard Deviation:

pg 65

What is normalization and why is it used in choropleth mapping?

A process of converting data values to a consistent level of data (such as percentage). Normalizing the values will prevent the data from being skewed and show correct values. (remember the unemployment example of Cali vs. Rhode Isle). pg 63.

What is the difference between normalized data and regular "count" data?

Count data is the data that would have been used and represented in the choropleth map BEFORE being normalized. This data would be shitty.

What is the cloud?

A computing structure where data, content, and resources are all stored at another location and served to the user via the Internet, where the data is normally stored on ESRI's data servers.

How is the cloud utilized in relation to GIS and geospatial data?

The cloud can be used to save data as a map package and have others download it via the cloud. You can also share the map package online as a Web map.

*What are SaaS, IaaS, and PaaS (and how does each relate to GIS and geospatial data)?

1) SaaS - Software as a Service: A cloud structure where the software being used is stored on a server at another location and accessed on-demand via the Internet (gmail).

2) IaaS - Infrastructure as a Service (Amazon, Google):

3) PaaS - Platform as a Service:

What is ArcGIS Online (and how is it an implementation of SaaS)?

It is Esri's cloud-based GIS platform where data and Web mapping software can be accessed via the Internet.

*What are the differences between the free and the organization level versions of ArcGIS Online?

Functionality. Some things will not be available for the free version. You can add, share, and manage content; add data to maps; store maps, apps, and data in the cloud.

What are the advantages of creating a Web Map rather than a Layout to present GIS results?

It is much easier to access up-to-date information and to retrieve information via a shared Web Map rather than a conventional paper map. Accessibility.

What are the advantages of distributing GIS maps and results with a Web Map?

What is a "service" in ArcGIS Online?

A format for GIS data and maps to be distributed to others via the Internet.

What does it mean to "publish" in Web Mapping?

Placing data or content onto a cloud server.

What is a feature service?

A hosted service that allows a user to share GIS data layers that can also be displayed, queried, or edited.

What is a tiled map service?

A hosted service that sets up GIS data as a series of image tiles that can be displayed, but not queried or edited.

What map projection is used with Web Maps?

Web Mercator Auxiliary sphere - the projected coordinate system used by ArcGIS Online.

What types of basemaps are available when working with ArcGIS Online?

A Bunch: Topography, Imagery, Imagery with Labels, Streets, National Geographic, Oceans...

What is a Web Application (Web App) and what is the difference between it and a Web Map?

A structure that uses shared content or data within a specific ArcGIS Online template.

Web Map: Interactive online representation of GIS data which can be accessed through the Internet.

What is a Storymap?

A web application designed to convey a specific theme or concept to the user using a special set of Web templates.

What is VGI?

Volunteered Geographic Information: User-generated geospatial data. pg 128

How is VGI data used in GIS?

pg 128

What are common sources of VGI online?

pg 128