Summer sci425_module_three_technical_writing_sample (2)
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Southern New Hampshire University *
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Course
425
Subject
Geography
Date
Jan 9, 2024
Type
docx
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5
Uploaded by SilverHorse333
Summer Brooks
SCI 425 Module Three Technical Writing Sample
Tutorial: Access Satellite Imagery Through ArcGIS
Key terms for this tutorial:
Composite image processing
: The composite image processing technique allows a GIS user to combine
multiple bands into a single raster. Although this is a somewhat complicated process, it allows the
raster to be viewed as a multispectral image in ArcGIS.
Normalized digital vegetation index image processing
: The NDVI is a standardized index that permits a
GIS user to generate an image that displays greenness. This band combination capitalizes on the
differences between the red band and near-infrared band to detect the presence or absence of green
vegetation.
Raster data set
: A raster data set is any valid format of raster data that uses one or more bands.
Mosaic data set
: A mosaic data set is a collection of raster data sets displayed dynamically in a GIS. This
format allows users to analyze larger swaths of imagery.
Image service
: An image service provides access to stored imagery through a web service. It allows a
GIS user to manipulate and analyze data stored on a remote server dynamically in a GIS.
1.
DRA
: DRA or dynamic range adjustment allows the GIS user to brighten and contrast the data
using only the data present within the data frame extent.
Open up a new ArcMap document.
2.
Access the ArcMap catalog and open the GIS server.
3.
Double-click
Add ArcGIS Server
and click
Next
on Use GIS Services.
4.
In the server URL, paste:
http://imagery.arcgisonline.com/arcgis/services
. Next, click
Finish
. Now
the ArcGIS on Imagery service should be available. Once the imagery service has been added,
open the Imagery service and expand the LandsatGLS folder. Add the TM_Multispectral_1990
Image data set. The resulting image data set should be similar to the one pictured below.
5.
Once the TM_Multispectral_1990 Image data set has been added, zoom to a city of interest.
6.
The city you are studying may look dark due to the stretch value of the image is using the entire
world to assign values. Go ahead and open the image analysis window (in the window drop-
down tab) and left-click the pin button and the TM multispectral 1990 so that it is highlighted.
7.
Once you have opened your image analysis window, click on the
DRA
button. This should
brighten your imagery because the values are stretched to use only values within the current
extent. Adjust the contrast and brightness filters until the image is enhanced to your preference.
(Aerial of Phoenix)
8.
Next, create a bookmark and label it ‘yourcityextent’ (e.g., Phoenix extent).
9.
Once the bookmark is created go to the processing section of your image tab and left-click the
clip function. The clip function will create a new raster data set the size of the current extent.
TIP: Export the new raster data and save it to your computer, e.g., Phoenix1990. (This could
serve as a 7 band Raster data set to conduct a temporal analysis.)
10.
Deactivate the TM_Multispectral_1990 Imagery service so that your clip is the only raster data
set that is currently visible. Make sure the clip is highlighted within the image analysis window
and then return to the processing area. Left-click the green leaf aka the NDVI function. A new
NDVI raster data set will be added to ArcMap for your city.
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11.
After you have created the NDVI for your city, turn off the NDVI layer and return to the clip.
12.
Access the properties of the clip and change the
bands to Red-4, Green-3, and Blue-2. The
resulting image is an excellent band combination
for isolating vegetation from non-vegetation by
taking advantage of the near infrared.
13.
Return to your catalog/GISimagery and drag in
TM_Multispectral_2000 and
TM_Multispectral_2010.
14.
Using the clip function in the analysis window,
create two new raster data sets for the year
2000 and the year 2010 using the same extent as your 1990 raster. Save these rasters as
yourcity2000 and yourcity2010 (e.g., Phoenix2000 and Phoenix2010).
15.
PRO TIP: You can easily compare changes within these rasters by turning the layers on and off or
by using the effects toolbar’s swipe function. (You must active effects within the customize
window/toolbar.)
Part Two -
The research method that I will use for this final project is by using field research from others and
analyzing data. I believe these are some of the best methods to use when focusing on geoscience
topics. Field research allow people to collect and experience data in person, rather than in a
laboratory. Analyzing data will help me understand the field research that I am performing. For
example, when I analyze data concerning past weather, I will better understand what I experience and
come across in my field research.
For my specific topic, I am studying dust storms in Arizona. I will use the data of past weather, wind
patterns and air temperature. The wind patterns will help me understand the impact of the dust
storms, such as how far the dust storms traveled, what debris they displaced and how it impacted
landforms.
The data I collect will be combined to create an interactive map on ArcGIS. I want to display the dust
storms, their size, their travel distance, what areas they began to grow in size and if the air
temperature had an impact.