1. 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%

2. 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.

3. San Antonio in 1986 after the size change

4. San Antonio in 2003

5. Braunig Lake
1986
2003

6. 1604 and I-10 Interchange
Now Fiesta Texas
Quarry is larger
1986
2003

7. Kelly Air Force Base
1986
2003

8. Hwy 281 and Loop 1604
2003
1986

9. San Antonio Airport
2003
1986

10. 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.

11. Isodata image of San Antonio with Maximum Iterations set to 5
9 different classes (colors)
10 different classes (colors)

12. Braunig Lake
Isodata Image
Isodata Image

13. 1604 and I-10 Interchange
Isodata Image
Isodata Image

14. Pixel Count for Isodata Difference
Initial State
Class 1
Class 2
Class 3
Class 4
Class 5
Class 6
Class 7
Class 8
Class 9
Class Total
50435
594792
263209
81589
31816
590326
145951
Class 10
Final State

15. Percentage for Isodata Difference
Initial State
Class 1
Class 2
Class 3
Class 4
Class 5
Class 6
Class 7
Class 8
Class 9
Class Total
100
Final State

16. 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.

17. K-Means image of San Antonio with Maximum Iterations set to 5
5 different classes (colors)

18. Braunig Lake
K-Means Image
K-Means Image – 1986

19. 1604 and I-10 Interchange
K-Means Image
K-Means Image

20. Pixel Count for K-Means Difference
Initial State
Class 1
Class 2
Class 3
Class 4
Class 5
Class Total
524655
898480
163996
Final State

21. Percentage for K-Means Difference
Initial State
Class 1
Class 2
Class 3
Class 4
Class 5
Class Total
100
Final State

22. 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

23. Class Stats Summary for 1986 Class Stats Summary for 2003
Class 1 – points (1.2011%)
Class 2 – points ( %)
Class 3 – points ( %)
Class 4 – points ( %)
Class 5 – points (6.2589%)
Class 6 – points (1.9388%)
Class 7 – points (0.7559%)
Class 8 – points ( %)
Class 9 – points (3.4700%)
Class Stats Summary for 2003
Class 1 – points (3.8298%)
Class 2 – points ( %)
Class 3 – points ( %)
Class 4 – points ( %)
Class 5 – points ( %)
Class 6 – points ( %)
Class 7 – points (7.2622%)
Class 8 – points (3.8427%)
Class 9 – points (1.1077%)
Class 10 – points ( %)
% 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%