Building Maps with UAS Data

Introduction

In this lab, we continued to learn more about the software, ArcGIS Pro.  More specifically, we learned how to take UAS data and put it into the context of a Geographic Information System software package (ArcGIS Pro).  This is currently one of the most desired skills in the UAS world. Through this, we analyzed the data and became familiar with the core Geospatial concepts.  In the end, we created a map that meets the cartographic fundamentals and is functional. Before we get to that, the questions below provide an introduction and background that would be beneficial before continuing onto the project:

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

• Proper cartographic skills are essential when working with UAS data, as it allows the proper context and information to be paired with the data.  Without proper cartographic elements added to the UAS data, the data would be just data and the end user would not know the necessary information to actually analyze what is going on.

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

• The essential elements that must be included in turning either a drawing or an aerial image into a map are a title, a north arrow (large scale and 3D maps mostly), a scale bar (avoid with Oblique 3D maps), a locator map (scale depends on the viewer), and a legend.  It is also vitally important to include metadata with the map, as it allows the map to be understood fully and further investigated in future uses. It is important as well that a watermark is included, so the credit of the project can be properly attributed.

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

• Spatial patterns of data can tell the reader the information that is trying to be conveyed such as possible trouble areas in the nutrition levels of soil.  A few examples of how spatial patterns of data can be used for conveying population density of cities across the United States, activity levels of aviation in certain areas of the country, flooding in a particular state, and crime rates in the various states.

What are the objectives of the lab?

• The objectives of this lab are to further expand our knowledge of the software, ArcGIS Pro.  More specifically, it is to learn how to take UAS data and put it into the context of a Geographic Information System software package (ArcGIS Pro), as this is one of the most desired skills in the UAS world.  Through this, we analyzed the data and became familiar with the core Geospatial concepts. In the end, we created a map that meets the cartographic fundamentals and is functional.

Methods/Lab Assignment

The goal of this lab as mentioned in the introduction was to take UAS data and put it in the context of a Geographic Information System, or in this case, ArcGIS Pro.  The data we used was provided to us from Dr. Hupy. The mission was flown on June 13th, 2017 by Peter Menet, and it was of the Wolf Creek Paving Company’s property in Milwaukee, Wiscousin.  This kind of UAS work is very common, as it is critical for the safety of the workers to know the slopes and elevation of the aggregate that surrounds them. If this is not done and the aggregate is continued to be stacked higher and higher, it can cause a failure of the structure of the aggregate and can harm the workers.  Due to this, the functions of hillshading, slope, aspect, and oblique will be used to hopefully prevent any sort of hazard.

Every project needs an organized file management, as this is crucial to locate the necessary data needed.  To start, a folder was created within the temp file of the computer for more efficient usage. Three folders were then created to better organize the data.  The first folder is for the “Collection” aspect which contains the pictures, videos, and any other similar data. The second folder was the “Processing” folder in which all of the ArcGIS Pro databases and files will go into.  The third folder is the “Analysis” folder which will serve as the storage folder for the copies of statistical analysis that will be done. This is done as an easy access location for data that will be presented in the final document such as the maps and any graphs created.  One of the key components that needs to be included in the folder is the metadata from the operation. Below, the metadata from this flight can be seen in Figure 1: Metadata of Wolf Creek:

Figure 1: Metadata of Wolf Creek

Below are additional questions and answers for better understanding:

What key characteristics should go into folder and file naming conventions?

• The key characteristics that should go into folder and file naming conventions are clarity and simplicity.  The names of these files and folders should be able to quickly portray the contents of it and the purpose it serves.  To add to this, it is important to have folders that separate certain file types. In class, Dr. Hupy strives for his students to have proper separation with a three folder setup.  The first one is the Collection folder which will contain the photos, videos, and other similar data. The second should be the Processing folder which contains all of the data from ArcGIS Pro such as the databases and files.  Lastly, the third folder should contain the Analysis folder that contains the copies of the final products that will be presented such as the maps and graphs. Without this, unnecessary energy and time can be spent on a project.

Why is file management so key in working with UAS data? How does this relate to the metadata?

• File management is so key in working with UAS data, as unnecessary energy and time can be spent on a project.  To be more specific, the data can become complicated and necessary pieces can be manipulated within the project, essentially destroying the data that has been collected.  This is where metadata can be so crucial. If the wrong coordinate system is used because the coordinate system that was used to collect the data has not been noted, the GIS software will reproject the data, and it can be highly inaccurate.  This is one of the worst mistakes that can be made, particularly if the user reprojects the points by entering in the perceived coordinates.

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

• Key forms of metadata that should be associated with every UAS mission are the sensor used, altitude flown, coordinate system of imagery, and the coordinate system of ground control GPS (if used).  To further this, we are taught to include additional information presented in Figure 1: Metadata such as the pilot, platform, data, and UAS coordinates.

After the file management was completed along with the adding of the data from Wolf Creek into the processing folder, the digital surface model (DSM) was added to the default basemap.  This can be seen below in Figure 2: DSM of Wolfcreek.

Figure 2: DSM of Wolf Creek

In order to allow for faster processing, pyramids were added to the project.  This function allows the software to clump the pixels together from a zoomed out view, making the processing faster.  This DSM allows the model to have 3-dimensional aspects that can be measured and analyzed. To add to this, an orthomosaic layer was added to the map.  This can be solely seen in Figure 3: Orthomosaic of Wolf Creek.

Figure 3: Orthomosaic of Wolf Creek

This layer can be added or removed from the DSM layer which will be demonstrated later.  For now, below are additional questions to further understand this project:

What basemap did you use? Why?

• The default general street map was used because it shows the layouts of the surrounding areas such as the roads and bodies of water that can be used for fining the location of this area of study.

What is the purpose of the pyramid and the calculate statistics command?

• The purpose of the pyramid is to allow for making the processing faster when viewing the DSMs.  The calculate statistics command allows for efficiently analyzing the raster data to find data such as extremes in elevation as well as the size of the cell.

Why might knowing Cell Size, United, Projection, Highest Elevation, Lowest Elevation be important?

• It is important knowing the cell size, united, projection, highest and lowest elevation, as it without this information, the data might not be represented entirely accurately and possibly lost.  Going back to what was mentioned previously, this information could increase the safety of the workers in the industry of study.

What is the difference between a DSM and DEM?

• A digital surface model, or DSM, represents the terrain’s surface in an area and includes things such as vegetation, bridges, roads, and buildings  A digital elevation model, or DEM, is a bare-earth raster grid referenced to a vertical datum. This model is corrected for what was mentioned above.  This means that these will not show up in the model, and rather, the models appear to be smoothed out. This can be seen in the examples below from Dr. Hupy’s project.

DEM vs. DSM

The next function that was added to the list of layers was the Hillshade.  This increases the perception of depth in a 3D surface by determining the illumination values in each cell of a raster.  The hillshade function can be done in two ways with the first being the traditional sense. This takes into account the location of the sun and casts the model that way.  An example of this can be seen in Figure 4: Traditional Hillshade of Wolf Creek.  The second way is Multi-Directional which essentially considers the sun in multiple locations throughout the day.  With this, it tends to show a little more details. This can be seen in Figure 5: Multi-Directional Hillshade of Wolf Creek.

Figure 4: Traditional Hillshade of Wolf Creek

Figure 5: Multi-Directional Hillshade of Wolf Creek

The next tool that was used was the Slope function.  This tool identifies the steepness at each cell of the raster surface.  This can be seen in Figure 6: Slope of Wolf Creek, and the legend of what each color represents in show in meters in Figure 7: Slope Legend of Wolf Creek.

Figure 6: Slope of Wolf Creek

Figure 7: Slope Legend of Wolf Creek

One of the most useful tools of ArcGIS Pro is the ability to stack layers and adjust their transparency for a complete analysis of the area.  In this lab, we stacked the slope layer over multiple other layers. Below, are all the layers we did this too, first being the slope over the DSM (Figure 8: Slope over DSM of Wolf Creek), second being Slope over DSM with Histogram (Figure 9: Slope over DSM with Histogram of Wolf Creek), and third being Slope over Hillshade (Figure 10: Slope over DSM with Histogram of Wolf Creek).   All of these have been adjusted to provide the most clarity.

Figure 8: Slope over DSM of Wolf Creek

Figure 9: Slope over DSM with Histogram of Wolf Creek

Figure 10: Slope over DSM with Histogram of Wolf Creek

A quick way to compare layers within a stack is using the swipe tool.  This uncovers the layer on top to be seen with the one below it. Additional questions and answers are below for further understanding of what was described.

What does hillshading do towards being able to visualize relief and topography?

• Hillshading provides a qualitative method for visualizing topography by producing a gray-scale 3D representation of the terrain surface with the sun’s relative position taken into account for shading the image.  This means that areas of high angles and slope will do darker due to high change whereas the lighter areas will be lighter because of less change.

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

• Orthomosaics are images stitched and scaled together with multiple layers.  DSM can help present the surface of these orthomosaics with the shaded relief, further indicating the rising and falling terrain depth.

What benefits does hillshade and 3D view provide? How might this relate to presenting this information to a client/customer?

• The benefit of hillshading, as mentioned above, is the ability to visualize the topography, showing the rising and falling terrain.  When adding in the 3D view, the elevation can really be visualized in the area of study. The combination of both can assist customers with visualizing the area being studied, indicating if any action needs to be taken.

What color ramp did you use? Why?

• The color ramp I used for the final map was one of blue shades.  I used this one because I wanted to have a visually appealing map that was not harsh to look at with a bunch going on.  I believe this is one of the reasons why the number of views is not as overwhelming as it could be. I made sure that all of the views used the same color ramp which I believed made it uniform throughout the final product.

How might these forms of value (Slope and Aspect) added data analysis prove useful to various applied situations?

• This applied situation required information that can be used to predict the movement of the aggregate, especially considering the erosion that will occur over time.  Due to this, it was crucial to add slope and aspect data, as with this, it can be analyzed to indicate the hazardous stockpiles

It is now time to compile these into a presentable map.  This is done by creating a Layout tab. The required data sets to include in the map(s) for this assignment are Slope, Aspect, Shaded DSM, and Orthomosaic.  There is no one way of doing this, so I decided to include all of these data sets into one map. I made sure I included all of the required elements talked about earlier such as the north arrow, scale bar, locator map, watermaker, and metadata.  The final product can be seen in Figure 11: Final Map of Wolf Creek.  In the future, I will probably separate them to provide a little more clarity. 

Figure 11: Final Map of Wolf Creek

Conclusions

Summarize what makes UAS data useful as a tool to the cartographer and GIS use.

• UAS data can be a useful tool to cartographers and GIS use, as it allows them to collect specific, up-to-date data on the area of study.  The means of collecting this data also tends to be much cheaper and efficient than traditional means. When it comes to GIS use, there is no doubt that the data is as accurate as it could be as well.

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

• The main limitations the data will have tends to be limited by the area of study itself.  It could be too risky to collect data in certain areas due to the natural boundaries, or obstacles, and airspace limitations.  The user should know most of the information that is included in the metadata section which includes the data, sensor and platform used, altitude flown, ground control coordinates and GPS, and UAS coordinates.

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

• Other forms of data that could be combined would be a previously collected data over time in order to compare the data, especially considering erosion patterns in the area.  The health of the surrounding environment could be useful as well to see the effects of the operations in that area.