GPS GIS Midterm

What does GPS stand for and what country operates it?

Global Positioning System, operated by the USA

What does GNSS stand for and how is it different from GPS?

Global Navigation Satellite System, runs all satellite systems such as GPS

What is the official name of the United States GPS system?

NAVSTAR

Name the 3 major systems of GPS

Space, control, user

Name the two core concepts that GPS relies on to calculate position

Time difference and satellite position 

How many satellites are in the GPS constellation and how many are operable at a given time?

32 satellites, 24 of which are operational and 8 of which are backups

Explain what trilateration is

Trilateration is similar to triangulation in radio telemetry except here you will find 4 points instead of 3. You take the areas that four satellites survey and where they all meet up shows you where you are in space. Time and position are used to calculate distance between a satellite and receiver. Distance = Velocity x Time

Name two broad categories of GPS use

Navigation and data collection

Why is GPS important for people or industries today?

Money, war, emergency workers, health care, insurance, homeland security, maps, wildlife, farmers, etc

What are two other GNSS systems used around the world (besides the U.S. system)?

Russia- Global Navigation Satellite System (GLONASS)

Japan – Quasi-Zenith Satellite System
(QZSS)

What kind of data specifically does GIS process?

Spatial 

Definition of Geographic Information System

A mapping system that visualizes geographic information about features by explicitly referencing them to locations on Earth's surface

Definition of Geographic Information Science

The science underlying the practice of GIS software design and use

Typical Functions of GIS software includes

• Data entry

• Editing

• Data management

• Analysis

• Output

Geographic Information Systems are used to answer questions about the following:

• Locations

• Conditions

• Spatial patterns

• Spatiotemporal trends and changes

• Inference

Please list three of five uses of GIS

• Mapping

• Measurements 

• Monitoring

• Modeling

• Management

GIS can stand for Geographic Information _ and _?

System and science

Define a system

A group of entities of activities that interact for a common purpose.

Name the 3 primary functions of GIS

Geovisulazation, geoprocessing, geodata

Describe the basic steps for recording a waypoint on a handheld GPS unit

First find the satellites. When you get to a spot that you’d like to mark select mark waypoint and then fill in the different areas such as name, description, etc. then save the waypoint once done

What are the two Google Earth Softwares?

Google Earth Web and Google Earth Pro

Explain what a placemark, path, and polygon are used for in Google Earth.

Placemarks are used to mark a specific location such as a coordinate, bench, your house, etc.

Paths used for identifying roads, trails
or boundaries

Polygons identifying areas or
parcels of land

What is ArcGIS Field Maps and what company owns it?

A program which allows you to create maps in the field with its streaming services which can track were you are and create borders. You can also make forms. It is owned by ESRSI

What platform must you access first when using field maps?

ArcGIS online

What is the filing convention for a Google Earth file? 

KML

What are the two types of data?

Quantitative and qualitative

NOIR

Nominal

Ordinal 

Interval

Ratio

Nominal 

Simply categorizes or classifies information 

Ordinal

Numbers used to place objects in order like rankings. Important to realize that we cannot assume that differences between values are equal.

Interval

Scale on which equal intervals between objects represent equal differences. Differences are meaningful. Each unit equal to another unit

Ratio

Has an absolute zero below which we cannot go. No negative numbers. Ratios can be calculated.

Variable categories

Continuous vs discrete and Independent vs dependent 

Data considerations 

Validity

Reliability

Bias

Variability

Natural variability 

Validity 

A valid measure is one that measures what it claims to measure. Accuracy 

Reliability 

A reliable measure is one that will give you or
anyone else approximately the same result
time-after-time, when taken on the same
object. AKA Consistency

Bias

A biased measurement is one that is
systematically off the mark in the same or
in one direction. AKA Inconsistency

Variability

Unpredictable errors or discrepancies that are not easily explained.

Natural variability

Variability is inherent in nature. We need to know how much variability to expect due to natural causes.