Lab3-Building Maps With UAS Data

Introduction

• Why are proper cartographic skills essential in working with UAS data?

        With UAS data there is always one very important piece to keep in mind, location location location. Where the data was collected, the flight path of the vehicle, and where to represent the collected data are all very crucial components. By having skills in the art of cartography one can clearly represent the data collected by a UAV and compare that data to other data sets. 

• What are the fundamentals of turning either a drawing or an aerial image into a map?

         The image must contain a scale bar, a north arrow, a reference window, a watermark, and metadata that allows the user to gain more understanding of the map.

• What can spatial patterns of data tell the reader about UAS data? Provide several examples.

        By adding spatial patterns the user can gain a greater understanding of the scale of the data being represented. It can be hard to gauge the size of a data set from a UAV because some can cover a large distance on a single flight, the result of which is large data. Adding spatial patterns such as a scale bar or a reference to something on the map itself, like a ground control station, the user can gain a greater understanding of the scale. 

• What are the objectives of the lab?

      The objectives of this lab are to create a proper UAS map that contains all of the fundamentals of turning an aerial image into a map listed above.

Methods

Working with the Data

• Start by copying the UAS data folder shown in the demonstration into your own folder for the UAS class. Be sure to name and organize accordingly. Answer the questions in italics below related to this data:
• What key characteristics should go into folder and file naming conventions

Folders and file names should be organized by the type of data and the data the data was collected. That way when selecting the folder it is easy to keep data types and separate flights organized.

• Why is file management so key in working with UAS data

UAS data can quickly gain a large number of files as multiple flights can be completed in a short period of time, and after a while, the amount of data collected can get very large. By having a strong file management system it will always be fast and easy to locate the files you are after while not accidentally getting data sets mixed up.

• What key forms of metadata should be associated with every UAS mission

These key forms of metadata can be seen below in figure 1.

• Create a table that provides the key metadata for the data you are working with
  

Figure 1: MetaData Table

• Add a basemap of your choice. Save the project with a pertinent name.
• What basemap did you use? Why?

I chose to use a topographic map because it provides a clear representation of the area that the data was collected from without having too many distracting background pieces such as roads. 

• Using the Add data icon, or Arc Catalog, bring the orthomosaic and the DSM into ArcMap
• Build Pyramids and Calculate Statistics for each data set.
• What is the difference between a DSM and DEM?

DSM is a flat photo and DEM has the elevation element

• Go into the Properties for the DSM and record the following descriptive statistics.
• Cell Size 0.02077, 0.02077, Units Meter (1.000000) , Projection WGS_1984_UTM_Zone_16N, Highest Elevation 323.08865356445, Lowest Elevation 281.04708862305
• Enter those statistics into a table. Why are these important?
  

Figure 2: Descriptive Statistics

• Generate a Hillshade for the DSM. Then set the original DSM to a color ramp of your choice and set its transparency to your choice over the shaded DSM. 
• What does hillshading do towards being able to visualize relief and topography?

Hillshading makes it easier to visualize the max and min and local terrain of the area. It provides a colored visual representation of the elevation changes on the map. A representation of this can be seen below in figure 3.

Figure 3: Hillshading

• Use the swipe tool to compare what you see in the orthomosaic to the DSM.

Figure 4: Swiping Tool

• How does the orthomosaic relate to what you see in the shaded relief of the DSM

The orthomosaic provides a sort of base map that allows the shaded relief to overlay on top so that the variation of elevation can be seen. Becuase it is an orthomosaic it has depth, otherwise it would just be a map. 

• Save your ArcMap project again (in case the software crashes). Open ArcScene.
• Add the DSM into ArcScene. Zoom to that layer.
•  Now add relief by setting the base heights to the elevation value. If needed, zoom to the layer again and adjust the vertical exaggeration.

Figure 5: Vertical Exaggeration

• What is the purpose of vertical exaggeration? What settings do you have for your data?

By exaggerating the data it allows for easier visualization of the terrain changes. Sometimes the changes might be minute and therefore hard to notice, so it allows for more noticeable change. 

• What color ramp did you use? Why?

I used a color scale of green to red. This logically makes sense because in the aviation world the more red colors signify danger because they are higher in altitude and the lower safer parts of the map are green. 

• What are the advantages of using ArcScene to view UAS DSM data vs. the overhead shaded relief in ArcMap. What are the disadvantages?

ArcScene allows the user to add features like background color and to expand the scale in order to better see the image. ArcMap allows the user to actually create a map by adding scale to the image. 

• Find a zoom setting and angle you like in ArcScene and export the image as a jpeg or file of your choice.

Figure 6: ArcScene Image

• Is this export a map? Why or why not?

No it is not a proper map because there is no scale or north arrow added to the image, so the user has no reference for the size or orientatoin of the image. 

Building a Map

·      Use the layout tab in ArcMap to construct a map (or series of maps) that meet all the needed criteria.

o   You can create one map that has the DSM and the orthomosaic in it.

o   Or you can create two maps where one has the orthomosaic and the other the DSM.

o   The exported oblique needs to be associated with the DSM, and provided with scale. As discussed in class, there are several ways to do this.

·      As a reminder, required map criteria:

o   North Arrow

o   Scale Bar

o   Locator Map (I demonstrated this, and have a video, but it was not in the methods area)

o   Watermark (this is a means for you to state you created your map)

o   Data sources and metadata (sensor, altitude, UAS platform, pilot)

Figure 7: Creation of Map

Figure 8: Map with Hill Shading

Conclusion:

• Summarize what makes UAS data useful as a tool to the cartographer and GIS user

UAS data can provide an aerial overview of an area due to the location of the vehicle while it is collecting data. This is great for a GIS user and cartographer because the aerial images and other data that can be collected are readily available to be made into a map or overlayed onto a base map for a GIS user. This provides quick and easy data use and visual representatin of the data. 

• What limitations does the data have? What should the user know about the data when working with it.

The user should be given the metadata attached with each flight so that it can be included on the map and proper adjustments can be made to the data if need be. The data is always limited to the equipment being used and the flight conditions on the day the mission was flown. 

• Speculate what other forms of data this data could be combined with to make it even more useful.

This data could be combined with previously collected statistical data, such as the tornado tracks file. If a flight was flown after every major tornado event and aerial images were collected, one could then overlay the images representing the damage done over the track of the tornado. Then, a user could click on the track of a particular tornado and see an orthomosaic of the track of the tornado.