Working in the GIS World

Wolf Paving Geospatial Build

The map above was created using data from a UAS. the following is question / answer style report that portrayed the process of creating a GIS map for a random data set. 

Part One:  Background

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

A: Data is just data unless it is processed and evaluated so that it can be used to express an idea. Tuning data into maps is a valuable way to express an idea that was captured using UAS. One must possess the proper skills to change raw UAS data into effective maps that communicate the intent of the data.

Q: What are the fundamentals of turning either a drawing or an aerial image into

a map?

A: To turn a drawing or image into a map it must have a scale and legend to give the reader a point of reference.

Q:What can spatial patterns of data tell the reader about UAS data? Provide

several examples.

A: Spatial patterns can show a reader different layers of comparison in the data. The use of color mapping height is one such example where using different degrees or tones of color would bring different objects into focus depending on the intent.

Q:What are the objectives of the lab GIS Build?

A: The objectives of this project were to become familiarized with GIS and how it can dramatically improve the quality of data collected using UAS.

Part 2:  Methods, Creating a map with reasoning behind each steps.

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. 

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

a.       Date

b.       Name

c.       Unique identifiers

2Q: Why is file management so key in working with UAS data

a.       UAS files may look similar to each other but represent very different sets of data

3Q: What key forms of metadata should be associated with every UAS mission

a.       Altitude

b.       Type of platform/Sensor

c.       Other optional metadata, pilot name, time of day, Weather conditions.

▪ Create a table that provides the key metadata for the data you are

working with

• Add a basemap of your choice. Save the project with a pertinent name.

Q: What basemap did you use? Why?

·       Road map

o   To give location awareness by using major roads as  guides.

o   Roads also give the reader a sense of scale without using a numerical bar scale

• 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.

Q: What is the difference between a DSM and DEM?

              DSM -digital surface model (includes objects on the surface) i.e. man-made objects.

              DEM- digital elevation model (does not include objects on the surface) i.e. terrain

• Go into the Properties for the DSM and record the following descriptive

statistics.

o Cell Size, Units, Projection, Highest Elevation, Lowest Elevation

o Enter those statistics into a table. 

Q: Why are these important?

              Gives the reader data they will need to compare relationships within the map or image.

• 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.

Q:What does hillshading do towards being able to visualize relief and

topography.

A: Enhances terrain associations that are differentiated by elevation.

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

Q:How does the orthomosaic relate to what you see in the shaded relief of

the DSM

A:  It adds context to the shaded relief.

• 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.

Q:What is the purpose of vertical exaggeration? What settings do you have

for your data?

A:  It exaggerates the differences in terrain elevations.

Q: What color ramp did you use? Why?

 A: Red to green. Red is often associated with high and green with low. Makes it more relatable to the reader without having to decode the color scheme.

Q:What are the advantages of using ArcScene to view UAS DSM data vs.

the overhead shaded relief in ArcMap. What are the disadvantages?

 A: Advantages are that the model can be rotated to put emphasis on select portions of the data. Disadvantage is that cardinal direction could be lost and scale could be skewed.

• Find a zoom setting and angle you like in ArcScene and export the image as a

jpeg or file of your choice.

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

              It is not a map, It would be a map if it had scale and a legend

Part 3: Conclusions

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

user,

              UAS data is a useful tool to the cartographer and GIS user as it opens up aerial imagery as a relatively cheap and easy way to gather data. UAS data, if properly gathered and organized, can be highly detailed and accurate to create extensive useful products  

• What limitations does the data have? What should the user know about the data

when working with it.

1.       Limitations that come with data are that it is only as good as how it was collected. If parts are missing like an accurate coordination system that links the image to a reference-able place, then the data set will be nothing more than an pretty picture.

2.       The user should know the following: how was the data collected, what are the different parts of the data, what was the purpose of collecting the data, and how will the data communicate the message of the final product.

• Speculate what other forms of data this data could be combined with to make it

even more useful.

1.       Historical data

a.       Previous images that show changes over time

2.       Additional ground reference points to depict more accurate terrain changes