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| Figure 1. Final Product |
In this weeks lab we applied the basics we learned last week and were introduced to some new functions of ArcPro. We were now applying ArcPro to UAS data and the new functions we introduced were raster functions for the slope and aspect of a digital surface model as well as creating an orthographic image within the layout. An example of which you can see in figure 1 above.
Why are proper cartographic skills essential in working with UAS data?
Cartographic skills are an essential part of UAS operations for conveying the information you have in a concise and understandable format. Cartography is both the creation of maps and the science and theory behind them. As such, cartographic skills include the ability to know what additional data is needed to make a map and how to layout the data on the map in a way that makes sense to the viewer. As our professor said a good map is one that anyone could pick up off the street and know what they are looking at. This is important because it gives value to the information you gather with a UAS.
What are the fundamentals of turning either a drawing or an aerial image into a map?
To my knowledge, to turn an image into a map requires a sense of scale, location, and orientation. Additionally all of the maps we have worked with so far have had some kind of legend for the information they contained.
What can spacial patterns of data tell the reader about UAS data?
Spacial patterns can be anything that gives meaning to data based on its relationship to its surroundings. An example of this would be elevation of an area where relatively low areas are shaded in cooler colors and relatively high areas shaded in warm colors.
What are the objectives of this lab?
The objectives of this lab were to learn what makes a good map and to create a map (or several maps) using UAS data in ArcPro. A good map for this lab meant including: a north arrow, scale bar, reference map, legend (when applicable), metadata, and a watermark. The north arrow gives a sense of direction and orientation, the scale bar a sense of scale of the area being viewed, the referance map shows where the area of interest is in the world, and the metadata shows how the data was collected and by who.
Methods:
Date Flown: June 13th, 2017
UAS Platform: M600 Pro
Sensor: Zenmuse X5
Altitude Flown: 70m
Ground Control GPS: Trimble UX5
Ground Control Coordinates: WGS84 UTM Zone 16
UAS Coordinates: WGS 84 DD
Pilot: Peter Menet
Example metadata used in lab
Once we got ArcPro up and running we began by making sure we were organizing our data appropriately as to avoid confusion and later. To do this, three folders were created in our computers main drive: 1 Collection. 2. Processing, and 3. Analysis. The collection folder contained any images, video, databases, and any other data we had to work with. The processing folder contained our ArcPro files, namely the GCP data. The Analysis folder contained our information as copies of the processing data as well as any images or projects we created in the lab, including the figures you see in this blog. Lastly we saved the project metadata in a text file outside of the folders for quick access
What key characteristics should go into folder and file naming conventions?
Folder management and file naming conventions are all about organization and ease of access. We have three broad folders for the three main steps of working with GIS data (collection, processing, and analysis). This makes the data easy to retrieve and to work with. The collection folder serves as a place or all raw information to be gathered and sorted as well as to serve as a backup should data in the processing folder be lost or otherwise unsuitable. The processing folder is a work space where the data we are currently working on can be stored and accessed. Finally the analysis folder serves as a collection for finished products, supporting data, and other analytics. I personally make another sub-folder within this folder just for deliverable items for the class.
Why is file management so key in working with UAS data? How does it relate to the metadata?
File management is critically important because, especially with GIS data sets, you may be working with a very large amount of data over many days. As such its important to have a file management system that is consistent to allow for quick and easy access to information that everyone can follow. Especially in a professional context where you may have multiple individuals all working on the same project at different times or on different portions of the data consistency is vitally important to ensuring that everyone working on the project can find what their looking for. This concept is mirrored within the metadata, where having a simple, concise and consistent data sheet is important.
What key forms of metadata should be associated with every UAS mission?
All UAS metadata sets should include: date, time, and location of the flight. The vehicle platform, sensor(s), and coordinate collection device used (i.e.gps). As well as the global coordinate system used.
Once our filing convention was set up, we put our data from the wolfcreek mining site from the previous week into the processing folder as this would be the data-set with GCP corrections we would use later. We added pyramids in order to make the image easier for the software to process and to make the images easier to interpret. Pyramids basically allow the software to generalize where pixels should be and without them the image would take a long time to load every time you viewed it or zoomed in and out on the image. Once the DSM data was added into the map we changed its symbology to RGB (red, green, blue) overlay as to better visualize the changes on elevation. We then used the aspect tool to identify the slope direction we were looking for. This raster function needed to have calculated statistics in order to run, thankfully ArcPro prompts you to do this when you use the aspect tool. These statistics, from my understanding, allow the program to interpret the colors projected on the map.
What basemap did you use? Why?
For this lab we used a general street map as it shows the layout of the area with landmarks like roads and bodies of water for orientation
What is the purpose of the pyramid and calculated statistics commands?
The purpose of the pyramid command is to make the data load faster and easier to view. The calculated statistics command is used by certain functions to gather specific data from map.
Why might knowing cell size, units, projection, highest elevation, lowest elevation be important?
All of these values are important for interpreting the data correctly as without them the map may be misleading or difficult to interpret whats being shown
What is the differenc between a DSM and DEM?
DSM (Digital Surface Model) shows the "raw" elevation of the terrain; it will show entities like trees, buildings, and other objects on the surface as part of the viewed image. A DEM (Digital Elevation Model) will remove those entities and try to correct the elevation based on what data it has. T put it simply a DSM will look like an aerial photo with trees, buildings etc. while a DEM will look smooth and only show the terrain
What does hillshading do towards being able to visualize relief and topography?
Hillshading shows the difference in angle in reference to a norm (usually, level). Areas with a high degree of slop or angle will show as darker colors and flatter areas with low slops will appear in lighter colors.
How does an orthomosaic relate to what you see in the shaded relief of the DSM?
An orthomosaic image can help you visualize the change in terrain of a DSM by allowing you to see the area from multiple angles and give you better perspective on the changes in terrain.
What benefits does the hillshade and 3D view provide? How might this relate to presenting this information to a client or customer?
Hillshading offers benefits like showing the difference in elevation of the terrain, while a 3D image can give you better perspective.
What color ramp did you use? Why?
I used a yellow to red color ramp for my slope model with is opacity turned down to about 50%. I chose this because it was a contrasting patter that was different from the RGB scale on my hillshade and different enough from a traditional thermal color scheme that it wouldn't be confused.
How might generated slop and aspect forms of added data analysis prove useful value to various applied situations?
Generated slope and aspect can be used by those in the mining or stockyard businesses; as this information can help miners see and track the movement or erosion of the earth over time. While those with stockyards can use this to calculate how much a material or mound is present and how much they may sell or move over a period of time.
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| Figure 2. Aspect Map |
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| Figure 3 Hillshaded DSM |
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| Figure 4. Orthomosaic View |
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| Figure 5. Slope Map |
Summarize what makes UAS data a Useful tool to the cartographer and GIS user
UAS data in conjunction with GIS is a very useful tool in cartography as it allows the user to cover a very large area quickly, and with a great deal of precision. It can also be used to access had to reach or dangerous places where traditional platforms may be unavailable or unsafe.
What limitations does the data have? What should the user know about the data when working with it?
The sensors and software aren't very useful for areas over large bodies of water or other reflective things as it can distort the image data. Airspace restrictions can also limit the scope of a UAS operation. Additionally, the processing of UAS data often requires a level of processing power not readily available to the average person and even if the infrastructure is in place to do such data processing it may take up to several days to fully process depending on the amount and type of data gathered. From the user side of things, one may be limited by their knowledge of the program in their ability to interpret the data; as ArcPro is a fairly expansive and nuanced program to use.
Speculate what other forms of data this data could be combined with to make it even more useful.
The data used in this lab could have been supplemented with a map of a water table or erosion map to better identify and track safety concerns to the operation. Additionally the same data we worked with in this lab could have been calculated over a longer period of time for a map of the change in the terrain over time.
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