Transcript ppt

Urban growth pattern of the San Antonio area
San Antonio population as of April 1, 1980 – 785,880
Average population of San Antonio for 1985 – 860,906
average between 1980 and 1990
San Antonio population as of April 1, 1990 – 935,933
San Antonio population as of April 1, 2000 – 1,144,646
% change in population from 1980 to 1990 = 19%
% change in population from 1990 to 2000 = 22%
% change in population from 1980 to 2000 = 46%
Received the image for San Antonio for 1986 from Dr. Xie
Used the image for San Antonio for 2003 from the images
given to in class from Dr. Xie
The image for 1986 was larger than the image for 2003
•Dr. Xie took the pixel location for the top left hand corner
and the bottom right hand corner of the 2003 San Antonio
image
•Dr. Xie inputted these locations into the image for 1986 to
so that they would be the same size and the same
geographic location.
San
Antonio
in 1986
after the
size
change
San
Antonio
in 2003
Braunig Lake
1986
2003
1604 and I-10 Interchange
Now Fiesta Texas
1986
Quarry is larger
2003
Kelly Air Force Base
1986
2003
Hwy 281 and Loop 1604
1986
2003
San Antonio Airport
2003
1986
Isodata unsupervised classification
Isodata calculates class means evenly distributed in the data
space and then iteratively clusters the remaining pixels using
minimum distance techniques.
Each iteration recalculates means and reclassifies pixels with
respect to the new means. Iterative class splitting, merging,
and deleting is done based on input threshold parameters. All
pixels are classified to the nearest class unless a standard
deviation or distance threshold is specified, in which case
some pixels may be unclassified if they do not meet the
selected criteria.
This process continues until the number of pixels in each
class changes by less than the selected pixel change
threshold or the maximum number of iterations is reached.
Isodata image of San Antonio with
Maximum Iterations set to 5
Isodata Image - 2003
Isodata Image - 1986
9 different classes (colors)
10 different classes (colors)
Braunig Lake
Isodata Image - 2003
Isodata Image - 1986
1604 and I-10 Interchange
Isodata Image - 2003
Isodata Image - 1986
Pixel Count for Isodata Difference
Initial State
Final
State
Class 1
Class 2
Class 3
Class 4
Class 5
Class 6
Class 7
Class 8
Class 9
Class Total
Class 1
50435
0
0
0
0
0
0
0
0
50435
Class 2
0
1264501
0
0
0
0
0
0
0
1264501
Class 3
0
0
1181173
0
0
0
0
0
0
1181173
Class 4
0
0
0
594792
0
0
0
0
0
594792
Class 5
0
0
0
0
263209
0
0
0
0
263209
Class 6
0
0
0
0
0
81589
0
0
0
81589
Class 7
0
0
0
0
0
0
31816
0
0
31816
Class 8
0
0
0
0
0
0
0
590326
0
590326
Class 9
0
0
0
0
0
0
0
0
145951
145951
Class 10
0
0
0
0
0
0
0
0
0
0
Class
Total
50435
1264501
1181173
594792
263209
81589
31816
590326
145951
Percentage for Isodata Difference
Initial State
Final
State
Class 1
Class 2
Class 3
Class 4
Class 5
Class 6
Class 7
Class 8
Class 9
Class
Total
Class 1
100
0
0
0
0
0
0
0
0
100
Class 2
0
100
0
0
0
0
0
0
0
100
Class 3
0
0
100
0
0
0
0
0
0
100
Class 4
0
0
0
100
0
0
0
0
0
100
Class 5
0
0
0
0
100
0
0
0
0
100
Class 6
0
0
0
0
0
100
0
0
0
100
Class 7
0
0
0
0
0
0
100
0
0
100
Class 8
0
0
0
0
0
0
0
100
0
100
Class 9
0
0
0
0
0
0
0
0
100
100
Class
Total
100
100
100
100
100
100
100
100
100
K-Means unsupervised classification
K-Means calculates initial class means evenly distributed in
the data space and then iteratively clusters the pixels into the
nearest class using a minimum distance technique.
Each iteration recalculates class means and reclassifies
pixels with respect to the new means. All pixels are classified
to the nearest class unless a standard deviation or distance
threshold is specified, in which case some pixels may be
unclassified if they do not meet the selected criteria.
This process continues until the number of pixels in each
class changes by less than the selected pixel change
threshold or the maximum number of iterations is reached.
K-Means image of San Antonio with
Maximum Iterations set to 5
K-Means Image - 2002
K-Means Image - 1986
5 different classes (colors)
Braunig Lake
K-Means Image - 2002
K-Means Image – 1986
1604 and I-10 Interchange
K-Means Image - 2002
K-Means Image - 1986
Pixel Count for K-Means Difference
Initial State
Final State
Class 1
Class 2
Class 3
Class 4
Class 5
Class Total
Class 1
524655
0
0
0
0
524655
Class 2
0
1289047
0
0
0
1289047
Class 3
0
0
1327614
0
0
1327614
Class 4
0
0
0
898480
0
898480
Class 5
0
0
0
0
163996
163996
Class Total
524655
1289047
1327614
898480
163996
Percentage for K-Means Difference
Initial State
Final State
Class 1
Class 2
Class 3
Class 4
Class 5
Class Total
Class 1
100
0
0
0
0
100
Class 2
0
100
0
0
0
100
Class 3
0
0
100
0
0
100
Class 4
0
0
0
100
0
100
Class 5
0
0
0
0
100
100
Class Total
100
100
100
100
100
What I did to find the pixel difference for the Isodata Classification
On the ENVI Main Menu
Click Classification -> Click Post Classification -> Class Statistics
Choose Classification Input file - Isodata Image for 1986
Choose Statistics Input file – Isodata for 1986
Selected All items
Asked for a Text Report
Repeated steps for the Isodata for 2003
Class Stats Summary for 1986
Class Stats Summary for 2003
Class 1 – 50565 points (1.2011%)
Class 1 – 145531 points (3.8298%)
Class 2 – 1266857 points (30.0916%)
Class 2 – 584474 points (15.3809%)
Class 3 – 1182127 points (28.0790%)
Class 3 – 636504 points (16.7501%)
Class 4 – 595314 points (14.1405%)
Class 4 – 577702 points (15.2027%)
Class 5 – 263499 points (6.2589%)
Class 5 – 533950 points (14.0513%)
Class 6 – 81625 points (1.9388%)
Class 6 – 467833 points (12.3114%)
Class 7 – 31823 points (0.7559%)
Class 7 – 275965 points (7.2622%)
Class 8 – 592105 points (14.0643%)
Class 8 – 146022 points (3.8427%)
Class 9 – 146085 points (3.4700%)
Class 9 – 42091 points (1.1077%)
Class 10 – 389928 points (10.2613%)
% Difference For:
class 1 = 188%
class 6 = 473%
class 2 = -54%
class 7 = 767%
class 3 = -46%
class 8 = -75%
class 4 = -3%
class 9 = -93%
class 5 = 103%