Lab#5: Data Sources and Management

I. Answer the following questions based on Bolstad Chapter 7 and lecture.

1. What are some advantages and disadvantages of using digital spatial data?
Advantages: Provides service information on "safety, health, transportation, water and energy." Required for disaster planning and management, national defense, infrastructure development and maintenance and government functions. Also pre-made data means you don't need to waste time making it. Disadvantages: Different governments specify different projections, data variables and attributes or have different requirements for survey accuracy or measurement units.

2. What are the most important questions you must ask before using already-developed spatial data?
Who Produced the Data? What requirements were used in creating the data? Is the data large or small scale? Does the data have what I need?

3. How do DOQs differ from regular photographs?
DOQ's are photos that have been altered to correctly represent an area or put it into a correct scale. Instead of leaving a raw photo that isn't spatially accurate. 

4. Choose three existing data sets and describe who produces them, what the source materials are and what they contain.
(1) Global Map. Produced by: Global Spatial Dataset Infrastructure. Source Material: Many countries contribute in giving information to make this data set. Contains: Boundaries, elevation, land cover and drainage. (2) National Hydrologic Data. Produced by: EPA and USGS. Source Material: USGS digital line graph data and EPA river data. Contains: Natural occurring and built features concerning water bodies (streams, dams, lakes) (3) National Atlas. Produced by: USGS. Source Material: 20 federal agencies. Contains: Political boundaries, environmental features, climate, history, biology, natural hazards.

5. What is the difference between DEMs and NEDs?
DEMs or Digital Elevation Models are raster data and have course resolution. They cover small areas with fixed boundaries that, if a larger area is needed, they have to be pasted together. NEDs (National Elevation Dataset) on the other hand are the highest resolution and seamless. Since DEMs came around they have removed the errors from the DEMs.

II. Step through the following instructions and answer any associated questions.

2.

 a) Basemap and Hydrology

b-c) NHDFlowline (line), NHDPoint (point), NHDWaterbody (polygon), Watersheds (polygon)

3.

a) Vector

b)SHP

c)yes

d)ArcGIS Geodatabase

e) yes

f) Hydrology, US, Artificial Path

g) Earth Science Information Center, USGS

4. a) Yes

6. b) 34118-B5

7. Black and White

12. Red exclamation point and gray checkmark

Lab #4: Working with Map Projections

            Map projections are very important because they give us sphere data on to a flat surface. There is always a distortion that comes with any map projection. The map projections used for this exercise represent certain characteristics more than others. The equidistant preserves distance, conformal preserves shape and direction, and equal-area preserves area.

            In the equal-area projections I chose the Mollwiede and Bonne projections. Mollwiede the shape is fairly accurate although since it’s a representation of a sphere it makes areas smaller when it gets closer to the poles and bigger toward the equator. The actual mileage from Washington D.C. to Baghdad is 6,211miles but according to the Mollwiede it is 6,587miles and according to Bonne it is 6,035miles. Bonne looks especially distorted but it does keep the general shapes of the continents except for Australia, which is very stretched.

            Equadistant projections are meant to preserve distance, which is proven by the maps. In Sinusoidal the areas closest to the poles are the most stretched/distorted. Otherwise, the map is fairly accurate. The Washington D.C. to Baghdad distance on this projection is 6,774miles. The distance for the second equidistant projection, Equadistant Conic, is 6,341miles, which is closest to the actual mileage out of all the projections. This map is very distorted because the continents near the North Pole are very small and as you go to the South Pole the continents get bigger making Antarctica look the same size as the rest of the continents combined.

            The conformal projection, Gall Stereographic, is a common sight when it comes to maps but it does blow the north and south poles out of proportion and keeps the rest of the continents shaped correctly. In the conformal projections the longitudinal lines are made even which keeps the direction right. The Mercator is extremely distorted at the poles. This projection puts the distance between Washington D.C. and Baghdad at 8,395miles which is very far from the correct mileage and the Gall Stereographic projection is only a bit closer at 5,942miles.

Coordinate Systems & Projections Worksheet

1. What is an ellipsoid? How does an ellipsoid differ from a sphere? 
An ellipsoid is an even oval shape that represents the shape of the earth. A sphere is different from an ellipsoid because it is perfectly round where an ellipsoid has a more squished shape.

2. What is the imaginary network of intersecting latitude and longitude lines on the earth's surface called? 
Geographic Coordinate System

3. How does the magnetic north differ from the geographic North Pole? 
The magnetic North is where a compass points because of the magnetic pull where the Geographic North Pole is one of the points the earth's axis rotates from.

4. Why are datums important? Briefly describe how datums are developed. 
Datums are important because they give us a better representation of the earth's surface that is more detailed than latitude and longitude. Datums come from points surveyed in a specific region or country.

5. What is a map projection? 
The process of putting the round earth on a flat surface: 3-D to 2-D and there are many different ways to do this effectively.

6. What is a developable surface? 
A shape which the earth is transformed from an object to a flat surface, for example a cone or cylinder.

7. Which lines on the graticule run north-south, converge at the poles, and mark angular distance east and west of the prime meridian? 
a. Lines of longitude
b. The major axes
c. Parallels
d. Lines of Latitude 

8. Which of the following ellipsoids is now regarded as the best model of the earth for the region of North America? 
a. Clarke 1866
b. International 1924
c. GRS80
d. Bessel 1841 

9. Which well known coordinate system would be appropriate to use for developing and analyzing spatial data when mapping counties or larger areas? Why?
Universal Transverse Mercator System, because it separates large areas into areas of 60 degrees longitude.

10. What is a great circle distance? 
The shortest distance between two points on a sphere but by drawing a line on the outside of the sphere and not going through it.

Lab #3: Data Formats & Models

Lab #3: Data Formats & Models
Geog 206: Intro to GIS
Fall 2010


I. Answer the following questions based on Bolstad Chapter 2 and lecture.


1. What is a data model? Describe the two most commonly used data models.
A method to create the world and it's features in a computer. The two most common data models are Vector ,which uses points and coordinates to represent features, and Raster, which uses a grid and cells to represent features.


2. What is topology and why is it important?
"The study of geometric properties that do not change when the forms are bent, stretched or undergo similar geometric transformations." Topology is important because it helps create relationships between features.


3. What type of data model would be best for representing hillside slope? Justify your answer.
Vector data model is best for representing a hillside slope because it gives more detail in a small area and gives direct points and lines which can represent the elevation/slope best.


4. Describe the relationship between spatial detail and cell dimension with regard to raster models.
The relationship between spatial detail and cell dimension has to do with resolution. The ground is represented by a cell and depending on how detailed you want the ground to be you want more cells representing an area if more detail is needed.


5. What are the four types of attribute data? Give an example of each.
Nominal=Zip Codes, Ordinal=harness of minerals, Interval=degrees in Fahrenheit and Celsius, Ratio=weight


6. List two types of vector data file formats.
Shapefile and geodatabase


7. List two types of raster data file formats.
Grids and graphs




II. Answer the following questions using the data/tutorials supplied in Ormsby
Chapter 4.


8. You can do all of the following in ArcCatalog EXCEPT:
a. Identify features
b. Copy data
c. Select features
d. View metadata


9. In the Chapter 4 exercises, does the World.mdb geodatabase contain a feature dataset?
Yes


10. What are the names of the feature classes contained in the World.mdb geodatabase?
cities, countries, disapp_area, and world30


11. What data format does the flight_path.lyr layer file reference?
Vector digital data


12. What are two ways to add data to an ArcMap document?
In ArcCatalog click on data and drag to ArcMap box or in ArcMap click on the yellow diamond with the black plus sign in the main toolbar, which is the add data button.


13. How many features (records) exist in the dissap_area feature class?
699


14. How can you determine this using ArcCatalog?
Under Metadata --> Attributes and under details for dissap_area it says Number of records: 699




III. Complete the ESRI online module “Basics of the Geodatabase Data Model” and
post a screenshot of the certificate.

a. To access, click on the following url: http://training.esri.com/gateway/index.cfm?fa=mytraining.gateway
b. Go to My Virtual Campus Courses. You will have to create a new account if you do not already have one.
c. Once you create the account and log‐in, go to Start a new course.
d. Enter the course code I provided you and start the module. (I will post these code assignments on Moodle)


Due: Wednesday, September 15th, 2010


Announcement: Quiz #1 has been shifted to September 13th and will include all of the information from Lab #1 through Lab #3.

Lab #2:ArcGIS & ArcMap

Lab #2: ArcGIS & ArcMap
Geog 206: Intro to GIS

Fall 2010


1. What types of software products are included in ArcGIS and which one will we be using most in this course?

The three types of software products included in ArcGIS are ArcMap, ArcCatalog, and ArcToolbar. We will be using ArcMap the most.

2. Would it be better to perform most of your data analysis and layer symbolization in data or layout view? Why?

It would be better to perform most data analysis through data view since it's easier to navigate and easier to edit layers, also because it lets you edit in single frames.

3. What are two ways to obtain help for ArcGIS Desktop?

Two ways to obtain help from ArcGIS Desktop is by clicking shift F1 or by left clicking on the help button on the far right of the main toolbar.
4. How are attributes linked to geographic features?

Attributes are linked to geographic features through a unique ID in a row of the attribute table.

5. What is the file extension of an ArcMap document?

The file extension of an ArcMap document is .mxd.

6. What are two ways to zoom in/zoom out on a map?

Two ways to zoom in/out on a map is by using the scroll on the mouse by rolling it up or down or by selecting the magnifying glass in the floating toolbar.

7. List three operations available in the ‘context menu’ of a layer. Hint: Right‐clicking with your mouse in the TOC should help you with this question.

Three operations available in the 'context menu' of a layer are open attribute table, zoom to layer and convert features to graphics.

8. If the check box next to a layer in the table of contents is grayed‐out, what does this mean? How would you resolve this issue?

If the check box next to a layer in the table of contents is grayed‐out it means the layer is not visible because the map is too far zoomed out and to fix it right click on the layer in the TOC and click 'zoom to make visible.'

9. What are the differences between large and small scale maps? Provide an example of each.

Large scale maps means the scale ration is large which means the map is zoomed in, for example a map of a city. Small scale maps have a small scale ratio which means you see more area, for example a map of the world.
10. Describe the differences between features and surfaces. Provide an example for each.

A feature is something located on the map whereas the surface is the ground area of a map. For example a feature might be a church and the surface would be the plot of land the church sits on.
11. A GIS is a useful problem‐solving tool. You can do all of the following tasks with it, except one. Which one?

a. Create project criteria

b. Query data

c. Display data on a report

d. Store project data

Using the existing ArcMap document “Ex03c.mxd”, and the knowledge and skills you have gained from the Chapter 3 exercises, answer the following questions:

12. What are the minimum and maximum elevations of the cities Earhart visited? Briefly describe how you determined these values.

The minimum elevation is in New Orleans at 0 and the maximum elevation is in Tucson at 1,045. To find these values open the attributes table for 'cities Earhart visited' and sort the elevation ascending. Now you can find the minimum and minimum elevations.

13. On the continent of Africa, what is the approximate distance (in miles) from Dakar to Assab? What are two techniques (one tool and one process) you could use to figure this out?

The distance between Dakar and Assab is 4,212 miles. Two ways to figure this out are selecting the ruler in the floating toolbox and clicking on one city and then the other or opening the attributes table for 'flight path' and highlighting the lengths of the from cities Dakar and Massawa. Then right click on the header length and select statistics and there you will find the sum.

14. What are two possible methods you could use to figure out the names of the cities shown on the map?

Two ways to find the names of the cities on the map are by scrolling over the cities or under properties for the layer 'citeis Earhart visited,' under the labels tab check the box 'Label features in this layer.'
15. Zoom to the extent of North and South America so that all the cities Earhart visited are labeled. Capture a screen shot (Alt + PrtScr) of this view and paste into your Word document (Ctrl+v). Turn in this screen shot with your answers from this sheet.



Due: Wednesday, September 8th, 2010

lab 1a: GIS on the Web

1.
A) About.com : A Geographic Information System, or GIS, integrates, data, hardware, software, and GPS to assist in the analysis and display of geographically referenced information.


B) webopedia.com : Short for Geographic Information Systems, tools used to gather, transform, manipulate, analyze, and produce information related to the surface of the Earth. This data may exist as maps, 3D virtual models, tables, and/or lists.


C) GIS.com : A geographic information system (GIS) integrates hardware, software, and data for capturing, managing, analyzing, and displaying all forms of geographically referenced information.


All these definitions are very similar. A and C both say they "integrate" tools, whereas B describes GIS as tools instead of integrating tools. They all agree that GIS helps in analyzing or assisting geographical information.  Definition B is the only one that gives example of what GIS can look like such as "maps...tables." Although these definitions have their slight differences they pretty much say the same exact thing as each other. 
This lets me know that the field of GIS is useful for multiple purposes but in the end it is used mostly for gathering and analyzing data  to explain information geographically.




2.
A) http://www.gismaps.fema.gov/gis04.shtm : FEMA uses GIS to map potential and current disaster relief operations. One example is storm tracking and constructing a map of potential damage. They can also predict and map/graph such things like hurricanes. 


B) http://www.nps.gov/gis/intro.html : The National Park Service uses GIS in the big picture to help protect and sustain a park for the next generation. They map where water areas are and where other objects exist to help visitors know where to go or where to avoid as well as help researchers who come into the park and have a head start on where to go and what to evaluate.

C) http://eworkscompany.com/index.php?option=com_content&view=article&id=105:gis-implementation-to-support-poverty-reduction-policy-and-drought-management-in-ethiopia&catid=46:papersarticles&Itemid=87 : In Ethiopia they use GIS for "drought management and rural development." They also try to use it for drought warning to help prevent famine. GIS is still being tested out as how effective it is for Ethiopia and how much more or less it needs to be used to be a real help.


3.
Both GIS and Maps are spacial data, they both reperesent a certain area and can give lots of detail in an area or very little detail.
GIS is different because it also includes the analysis part of data and shows data in other ways away from a map.