Lab 2: Working With The Data

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Introduction


  • What makes data geospatial? That is, what makes the data you worked with today geospatial in nature (think coordinates)?
    • Geospatial data contains a geographic component in the data set to recognize locations through geographic coordinate systems or other locating systems.  

  • What makes data in a GIS different than a digital map?
    • The metadata behind GIS, a digital map may only contain a scale and a range of coordinates. With GIS data you are able to analyze each individual point within a data set. 

  • Why is having an understanding of geospatial concepts and geospatial data so fundamental to working with UAS data?
    • It gives UAS data the ability to become a working map with specific geographic information and not just images. 

  •  What are some of the key geospatial concepts and fundamentals that this lab addresses?
    • The types of data that are used in GIS, Geographic Coordinate systems and how they are used and projected, the types of files associated with GIS data and GIS and UAS data integration. 


Method


  • Open the Tornadoes folder and find the Tornado_tracks files. List out each file with its extension.
    • .dbf, .prj, .sbn, .sbx, .shp, .shx

Figure 1.1: Tornado_tracks files. 












  • Why is file management so key in working with UAS data?
    • Do to the fact that there are so many files that comprise one GIS file. Shown in Figure 1.1.

Arc Catalog

  • What is the purpose of establishing a folder connection?
    • To access the files needed to analyze data within ArcCatalog and ArcMap.

Figure 1.2: ArcCatalog File Structure
  • What is the difference between viewing the files in Arc Catalog vs. Windows explorer?
    • There are many more files when opening in Window than when opening in ArcMap/ Catalog. These are the files that make up the few GIS files.
  • Why is it so important, beyond maintaining proper file management/naming, to use Arc Catalog for managing your GIS data?
    • Using ArcCatalog makes viewing and sorting through the .shp files much easier. You can than access the files needed through ArcMap.
  • What do those icons mean? Hint: Use the preview tab to view the file
    • The icons show which type of data the file contains, for example whether the data is points or polylines, raster or shape. 
  • List out each of the geospatial data types, and then provide an example file for that data type.
    • Raster, point, line and polygon.

  • What topic/term relates to this description tab?
    • Extent: gives the boundaries of the data set.

  • Why is having this information so important in the UAS realm?
    • To understand where you data set is located, it gives geographic locations to the data points within the map you created. By seeing the geographic boundaries of the data you can tell if you have covered the entire subject area or if the flight was unsuccessful. 

UAS Raster Data 

Wolfpaving

  • What does it say? (Properties)
    • Not calculated
  • What types of tasks rely on statistics?
    • Applying a contrast sketch or calculations with regards to mean elevation or other such statistics.
  • List the Min, Max, and Mean elevation of the DSM.
    • Min: 281.05
    • Max: 323.09
    • Mean: 297.97
  • Why would this information be important for data processing, analysis, and communication with the client? (Think of what was discussed in lecture/demo)
    • Having this data calculated allows the client to be able to understand and comprehend the data they are looking at. They are able to see changes in elevation within the area of study. 
      • Cell Size: 0.02077, 0.02077
      • Format: TIFF
      • XY Coordinate System: WGS 1984 UTM 
      • Linear Unit: Meter
      • Datum: D WGS 1984
      • Use the Linear unit and write the pixel size in square cm: 
        • 2x2
        • 4cm^2
Figure 1.3: Properties Calculations Wolfpaving

ArcMap 


  • Referring to your notes from the demo/lecture, list out some different ways to add data. (In ArcMap)
    • Directly from the catalog window, the add data button on the tool bar, from the file drop down menu. (Figure 1.2 and 1.4)


Figure 1.4: Adding a Basemap from the tool bar

  • What basemap did you use? Why?
    • Topographic to show elevation. (Figure 1.4)

  • What type of GIS data is this? Justify your answer.
    • Vector, polygon shape file. We can tell this from the icons pictured next to the file in ArcCatalog or by using the information tool and clicking on a point or line. (Figure 1.5)

  • What type of GIS data is this? Justify your answer.
    • Vector, line shape file. We can tell this from the icons pictured next to the file in ArcCatalog or by using the information tool and clicking on a point or line. 

  • What type of GIS data is this? Justify your answer.
    • Vector, point shape file. We can tell this from the icons pictured next to the file in ArcCatalog or by using the information tool and clicking on a point or line. 

Figure 1.5: Point shape file example

Figure 1.6: Tornado Tracks and Hydro Features. 

  • Write down the Coordinate System: 
    • Projected: NAD 1983 UTM Zone 16N
    • Geo: GCS North American 1983

  • Now write the coordinate system for the other two data layers.
    • Dam: 
      • Geo:  GCS North American 1983
    • States: 
      • Projected: USA Contiguous equidistant conic
      • Geographic: GCS_North_American_1983

  • Are all of these coordinate systems the same? Why might that be an issue?
    • They are not all the same projected coordinate system, but all have the same geographic coordinate system. This can be an issue by having different DATUMS or being different projections. This can affect the location of the data points and line and the accuracy of your data. 


  • How might the need for metadata relate to coordinate systems.
    • When clients are viewing the data they are able to see which type of coordinate systems was used and are able to know how to locate the points and positions that are on the map.

Attribute Data 

Figure 1.7: Tornado Tracks Attribute Data
  • Think of some different types of attribute data that could be used in conjunction with UAS data and list it here with a use example.
    • Other types of attribute data could include but is not limited to flooding areas, forest fires, natural disasters, rain and other weather patterns. 

UAS Data: Wolfpaving DSM


  • What type of data is this?
    • Raster 

  • What is the format?
    • TIFF

  • What is the projection?
    • Linear, transverse mercator. 

Figure 1.8: Wolfpaving Orthomosiac.

  • What is the projection?
    • Transverse Mercator, WGS_1984_UTM_Zone_16N

  • Does this projection match the Ortho? Why is this so important?
    • Yes, to ensure that the data points on the ortho are accurate. 

  • Do the points line up with the markers on the ground?
    • Yes, reference Figure 1.9 below. 

Figure 1.9: Ground control points, wolfpaving. 

Tools

  • Measure: Measure several features on the map. How might this type of tool be useful in working with UAS data?
    • This tool will allow the user to measure boundaries and distances between multiple points when needed. You can calculate area of a feature with this too as well. (Figure 1.10) 
Figure 1.10: Measure Tool
  • Identify: Use the identify tool on several of the GCP points. Also, turn on the DSM and identify pixels on that layer. How might this tool come in handy when working with UAS data?
    • The identify tool allows the user to click on specific points and is able to view certain data specific to that point. (Figure 1.11)
Figure 1.11: Identify Tool
  • Swipe: Use the swipe tool to move between the Orthomosaic and the DSM. How might this tool be useful when working with UAS data?
    • This tool allows the user to "swipe" between 2 layers at a time. With UAS data it will be useful to swipe between an ortho and other maps to see if the data is matching up or to see other types of information that could be useful. 

Conclusion


  • Summarize what makes UAS data useful as a tool to the GIS user. 
    • UAS data is useful for a GIS user because it allows the user to take the UAS imagery and overlay that data into a more complex and functional map. The user is able to create 3D maps and orthomosiacs that represent the dataset and the project.

  • What limitations does the data have? What should the user know about the data when working with it.
    • The user needs to know what type of data they are working with and which geographic coordinate systems are associated with the date. It is important to be working with data that is using the same coordinate system to achieve the same projection, if not the data could be wrong or inaccurate. 

  • Speculate what other forms of data this data could be combined with to make it even more useful.
    • It is important to have metadata associated with the GIS and UAS data. Metadata can include data from the UAS flight such as the date, weather, altitude, flight platform and sensors used. By having this associated with your data it allows users and clients to have a better understanding of the data set and data collection.  




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