Lab #4 ....more to come

Lab #5

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 are readily accessible and can be use in various projects by various entities.  Directly transferred to other digital devices.  Disadvantages include different formats of data stored, inaccurate data and outdated data being used.

2. What are the most important questions you must ask before using already-developed spatial data?

Is this data relevant and up todate

3. How do DOQs differ from regular photographs?

Scanned aerial photographic images that have been corrected for distortions due to camera tilt and terrain displacement, and then are georeferenced

4. Choose three existing data sets and describe who produces them, what the source materials are and what they contain.

·         Digital Raster Graphic (DRG)-

·         Georeferenced raster image of a scanned USGS map

·         Usually 1:24,000 scale in the US

·         Stored in geotiff format (*.tif). Used for quick check for consistency in data collection and for navigation when displaying data.

·         Digital Line Graphs (DLG)-

·          Vector representations of features displayed on a USGS national series map often in SDTS format.

·         Provide a limited set of attribute information and are highly structured to convey topological relationships

·         Digital Elevation Models (DEMs)-

·         Elevation data in raster format

·         Created from ground and aerial surveys of original elevation measurements

·         Spatial resolution of 30 meters (often 10 meters)

·         USGS National Elevation Datasets –Primary delivery as a seamless data source.

·         Created for specific projects such as road construction

5. What is the difference between DEMs and NEDs?

NEDs provide higher resolution images for larger areas with greater accuracy.

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

a. What are the names of the feature datasets in the geodatabase?

Base map and hydrology

b. What are the names of the feature classes in the hydrology dataset?

NHDFlowline, NHDPoint, NHDWaterbody, Watersheds

c. For each one of the feature classes you just listed, describe whether it is a polygon, line or point layer.

NHDFlowline- line

NHDPoint- point

NHDWaterbody- polygon

Watersheds- polygon

3. Using ArcCatalog, answer the following questions.

a. Is topoq24.shp a raster or vector layer?

vector

b. What is the GIS data format of topoq24.shp?

SHP

c. Is there metadata associated with topoq24.shp?

yes

d. What is the GIS data format of the NHDFlowline layer?

ArcGIS Geodatabase

e. Is there metadata associated with NHDFlowline?

yes

f. What are 3 keywords used to describe the NHDFlowline layer?

FWHYDROGRAPHY, Hydrography, Stream / River

g. Who created the NHDFlowline layer?

Earth Science Information Center, U.S. Geological Survey

4. Export the NHDFlowline feature class to a shapefile format, name it NHDFlowline.shp and place in the Lab_5 folder on your C-drive.

a. Is there still metadata associated with the layer?

Yes there is

b. In the USGS_QD_ID field, find the value that corresponds to the Canoga Park QUAD_NAME. What is it? _34118-B5______

7. Load the DOQQ tiff into your Lab5 ArcMap document. Is the DOQQ black and white or CIR (color infrared)?

Black and white

8. Use the DOQQ and Highways layer to find the CSUN campus. Zoom to that location. Capture a screenshot (Alt+PrintScreen) and paste into a Word document with your other answers for this assignment.

9. Save your Lab5.mxd document and close ArcMap.

10. In ArcCatalog, navigate to your Lab5 folder. Capture a screenshot (Alt+PrintScreen) of the expanded folder/file structure and paste into a Word document.

12. Open the Lab5.mxd document again.

a. What happened to the lacounty_lu01.shp layer?

The La county disappeared

Lab #3: Data Formats & Models

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 data model is a set of rules/constructs used to describe and represent aspects of the real world in a computer. Geometric/Geospatial Data- defines spatial location and extent using usually coordinates or pair of numbers. Attribute data- captures non spatial info in an attribute table.

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

3. What type of data model would be best for representing hillside slope? Justify your answer.
Geospatial data would best represent a hillside slope when constructing a model of the hillside with spatial information

4. Describe the relationship between spatial detail and cell dimension with regard to raster models.
With a raster model cells represent the given information, with each cell having equal dimensions but different numbers of spatial info for each cell.

5. What are the four types of attribute data? Give an example of each.
Nominal- descriptive categorical data such as a house and a tree.
Ordinal- ranked and ordered data such as lists of smallest to biggest.
Interval- ordered data, with absolute differences in magnitude and arbitrary zero. Range of data along a live
Ratio- ordered data, with absolute differences in magnitude and absolute zero. A number line defined at an absolute zero

6. List two types of vector data file formats.
Shape files and coverages

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

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:
c. Select features

9. In the Chapter 4 exercises, does the World.mdb geodatabase contain a feature dataset?
no

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?
Raster format

12. What are two ways to add data to an ArcMap document?
Click and drag the data from ArcCatalog to the TOC in ArcMap

13. How many features (records) exist in the dissap_area feature class?
699
14. How can you determine this using ArcCatalog?
By accessing the metadata

15.

Lab #2: ArcGIS & ArcMap

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

ArcView, ArcInfo, ArcEditor. We will be using ArcEditor the most in this class.

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 in data view. This view allows you to explore, query or display information where you can edit or analyze data from a single frame.

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

To obtain help either press “shift+F1” or go to http://support.esri.com.

4. How are attributes linked to geographic features?

Attributes are linked to geographic features by a unique ID.

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

.mxd

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

Use the zoom in/ zoom out function on the tool bar by double clicking on an area or by clicking and draging to create a box that highlights a certain area.

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.

Add data, group layers, open attribute table.

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?

This layer is to small to be seen at your current veiwing scale. Zoom in to see where this layer is.

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

A large scale map has a small ground area shown with a lot of detail such as a city street map. A small scale map has a large ground area shown with not a lot of detail such as a country map.

10. Describe the differences between features and surfaces. Provide an example for each.

A feature is a geographic object in a layer, such as a lake, river or city. A surface is a xontinuous expanse that changes from one location of another such as an ocean.

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 maximum elevation was Tucson at 1045ft, and New Orleans at 0ft. To determine this I accessed the attribute table.

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?

It is appx. 6915 kilometers. One way is to select the attribute table of the flight path and summerize the cities from Dakar to Assab and take the sum of the flight path. The other way is to use the measurement tool and measure from city to city.

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

One way is to right click and turn the labels on for the cities Earhart visited. Another way is to use the information tool and to select a city.

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.