Danny Foley: Part I Geology, Topography, and Imagery
Region: Chiricahua SE AZ
What is the basic geology of the site?
The basic geology of this site is represented by its geologic units and relative ages which
include: Tv, Ti, KJs, Kv, Tsy, PP ,Yg, Tg, Pz, Qo, XmQTb, surrounded by Q. It is
mostly volcanic rocks mixed with some local sedimentary rocks with even fewer granitic
rocks surrounded by quaternary surfical deposits. These images suggest the area
represents a volcanic intrusion or possibly an uplift of volcanics exposed by erosion
amidst the surrounding nonvolcanic rocks.
How do you see that the geology is manifest in the topography and imagery?
In Chiricahua the volcanic rocks exposed are different and relatively higher in elevation
than base level surficial deposits. This difference in rock types at differing elevations is
clearly represented in all four data sets when combined with the topography layer.
Are the units resistant?
The units are resistant as overall the exposed volcanic rocks are clearly visible and
separate from the surrounding base level surficial deposits.
Can you see the contacts? Yes, the volcanic rocks are distinct from the surrounding
surficial deposits especially since they tend to be at relatively higher elevations and are
more vegetated. This area is mostly high desert with few trees at base level elevations
and “Sky Island” eco systems with forested high relief mountainous areas clearly
represented in red in the CIR and NDVI Images.
Could it have been mapped in more detail?
Yes, this area could have been mapped in more detail. The contacts on the geologic map
are not precise, rather gentle and broad and the contacts could mapped in more detail.
However there are clouds covering ~ 1/3 of the volcanic area of Chiricahua when these
images were taken which makes assessing detail problematic and results inferring from
the geologic and topographic layers.
CIR Image Only
CIR with Topography Layer
CIR with Geology Layer
NDVI Image Only
NDVI with Topography Layer
NDVI with Geology Layer
SWIR Image Only
SWIR with Topography Layer
SWIR with Geology Layer
TIR Image Only
TIR with Geology Layer
TIR with Topography Layer
Danny Foley: Part II--Urbanization changes around Phoenix:
Answer: what area did you choose? Northern Scottsdale/ Phoenix Arizona.
What kinds of changes in urbanization do you note?
There are some changes in urbanization observed in new features in the 2004 image
compared to the 2000 image. There no major changes in urbanization, rather relatively
minor changes revealing new developments or new additions to previous developments.
These differences are noted throughout the northern half of the images where there is still
open land to expand. There is a new expansion that looks like it may be a golf course in
Northwestern Phoenix/Cave creek in the far northwest phoenix region observed. In the
north central which appears to be anthem there is new developments observed in 2004
where in 2000 the land was cleared but did not have visible features. There is also some
additional expansion to existing developments in communities north east of the
McDowell Mountains and in the eastern Scottsdale/ Fountain Hills Area.
Which imagery product shows the changes the best and why?
The NDVI shows the changes between images best because of the high contrast between
light and dark. The fact that this is an arid desert environment with limited natural
changes in vegetation through out seasons it is reasonable to presume new vegetation is
associated with new development as neighborhoods and business will plant non native
grasses and trees that do not loose leaves in the winter. Therefore the sharp difference
from white represented by vegetation imposed on a black background or substrate reveals
clear changes in growth.
The other versions had too many colors represented to compare the changes in growth.
The TAR was the most difficult with various colors that did not allow changes to sharply
stand out. The SWIR was fair with blue sharply representing vegetation. CIR was good
however the 2000 image was not very clear with a bluish hue to the background in
addition to the reds while the 2004 images had more natural colors for the background
with rendering this image not as useful as it could be to compare.
How does the NDVI (measure of green vegetation) show the differences?
The NDVI images show the difference excellently between images. Since it is mostly
black and white, changes show up clearly. Measures of green vegetation are represented
in white as a sharp contrast to the black and darker background. This is very obvious in
the rectangular farmlands in the Central East and West.
What do you think the urban growth looks like now?
I think the urban growth now would be much more prevalent in the North
Phoenix/Scottsdale area almost 4 years later in late 2007. From experience, I know that
the area around and North of Desert Ridge off of Tatum, North of and around DC Ranch
off of Pima, and North of and around Happy Valley and the I-17 in the Anthem area is
expanding in construction rapidly. I did not detect rapid changes from 2000 – 2004 in
these areas as they were already laid out back then and were fairly new. Now that they
are established and successful I think the changes would be more obvious to detect from
remote sensing.
Are there any other landscape changes that you see?
Aside from urbanization there are obvious changes in farmland additions in the Central
East and West. New rectangular farming fields appear and expand, however this change
could be do the change of season between images.
How well do the images match geographically (use the measurement tool to measure
the distance between common features)?
I measured the distance from the center of ASU in Tempe to Sqaw Peak in the Phoenix
Mountains. The geographic distances do not match well. The distance varies between
images with results as follows:
CIR = 16,790.71 m
NDVI = 17,730.01 m
SWIR = 16,793.58 m
TAR = 18,120 m
CIR Scottsdale
NDVI Scottsdale
SWIR Scottsdale
TAR Scottsdale