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
