Advanced Image Processing of Coffey County Lake and John Redmond Reservoir

Cara Haas

May 2008


This webpage project was created for the ES 775 Advanced Image Processing course for the spring semester of 2008 at Emporia State University. The assignment was to demonstrate Advanced Image Processing techniques used throughout the semester.


Table of Contents


Introduction

The area of study used for this project is located in the southeastern portion of the state of Kansas in Coffey County. There are two major water bodies in this area; Coffey County Lake and John Redmond Reservoir. Coffey County Lake, formerly known as Wolf Creek Lake, provides cooling water for the Wolf Creek Generating Station's condenser water system. Here, steam is cooled, turning it into water, and then reheated to make steam again. This water source is a warm water area that has a limited amount of land cover, therefore providing a clear lake where submerged water plants grow rapidly. The second lake studied is John Redmond Reservoir. This reservoir is located in the broad valley of the Neosho River. The construction was completed in September of 1963 and was built for flood control, water supply, water quality, recreation and wildlife purposes. John Redmond is a shallow lake with a maximum depth of 12 feet. Below is a map, taken from the internet, of the study area.

Image taken from: coffeycountychamber.com/images/lakes.jpg

The purpose of this project is to study how the two lakes differentiate in comparison of suspended sediments to non-suspended sediments. I took pictures using a Fuji camera of both study lakes. The pictures below help illustrate how cloudy John Redmond Reservoir is compared to Coffey County Lake. Knowing this, I wanted to futher investigate why these two lakes differed in characteristics using Advanced Image Processing techniques and functions.

Coffey County Lake (Top Right), John Redmond Reservoir (Top Left)

The dataset used was an Aster image obtained from the the KGCC and DASC website. Three bands (Bands 1-3) were used with Idrisi Andes software to create the following images that portray different characteristics within each lake. The image used was taken on August 6, 2001.

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Processes

The first step of the image process was to obtain the Aster image. For this, DASC has a free downloadable Aster image of Coffey County and Osage County. Once the image was in Idrisi format, it needed to be cut into a smaller image that focused on my project site. The WINDOW function was used to accomplish this. The WINDOW function clips the images based on a user defined box, which use the top left and bottom right rows and column values. The values I used are in are in the following table:

Upper left column 3618
Upper left row 4340
Lower right column 1776
Lower right row 3017

After I had completed cutting the original image, I used Bands 1, 2 and 3 to created three different composites, Figures 1.1, 1.2 and 1.3, which follow:

Figure 1.1 (Top Left), Figure 1.2 (Top Middle), Figure 1.3 (Top Right)

The next image I created is a false-color composite using bands 3, 2, 1. This image is used to show active vegetation in shades of red. The darker red represents dense vegetation while the lighter shades represent less dense areas used mostly for agricultural purposes. I also thought that this image was beneficial in showing the contrast between lakes. On the left, John Redmond appears lighter, which indicates suspended sediment in the surface water whereas on the right, Coffey County Lake appears darker indicating less suspended sediment.

The image below is a composite of bands 1, 2, 3. Though the image ideally is suppose to represent true-color, because Aster does not have a true blue band, the image appears opposite with vegetation represented by a blue color and water bodies a golden or darker color. I thought this image was especially beneficial in showing the contrast between lakes. John Redmond appears a light golden color indicating movement among sediments which is also evident in other small parts of the image. In this image Coffey county Lake appears a dark color, almost black indicating a clearer water body.

I used the next two images to show comparison among vegetation and water bodies. I mainly created these composites to try working on different formulas. Figure 1.6 is used to emphasize water bodies. As you can see, they appear bright green standing out among the surrounding vegetation. This composite was created by using the green and near-infrared bands in the following formula: (green-NIR)/(green+NIR). Figure 1.7 was created to emphasize vegetation contrast again using the green and near-infrared bands but in the following formula: (NIR-green)/(NIR+green).

Using the previous created composites, the next image I created was using the CLUSTER function. This function separates features based on their spectral reflectance. So, similar objects and features are represented by the same color. For this image, six clusters were created with the water bodies being represented by clusters 5 and 6.

Using the CLUSTER image and the EDIT function I created an attribute file. First, I used the RECLASS function for the water bodies. Then I used the GROUP function to cluster the unique ID numbers using the following :

0: 2-6
1: 6-7

The following image, Figure 1.10, portrays the image created by the RECLASS and GROUP functions, using only two colors, red indicating water bodies and black the remaining area.

My final image was again created by the RECLASS and GROUP functions. Again, I used the unique ID numbers grouping the water bodies with similar attributes together. The final image, Figure 1.11, portrays three different groups. John Redmond appears a light aqua color, Coffey County Lake appears a dark blue and the non-water areas appear a light gray. This image is a simple way in showing the contrast between water bodies in regards to the sedimentation.

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Results

Lastly, using the AREA function I was able to construct a tabular form that results in the following table to compare the amount of acres of water-bodies compared to non-water bodies and the two different lake sizes:

Category Acres
0 122,005
1 7,299
2 6,364

In conclusion, with the use of Aster images I was able to study the characteristics of two lakes and why they are portrayed differently on images and photographs. As stated before, John Redmond is a shallow water body. Therefore wind and rain are able to stir up sediments from the lake floor of the reservoir. This factor, along with the movement of the Neosho River, causes a muddy appearance. Here, sunlight is unable to penetrate the water and is reflected back causing the lake to appear brighter in color on satellite imagery. In comparison, Coffey County Lake is deeper and does not have a moving water flow, therefore the sediment deposits remain conditionally stable. This characteristic gives the water a more clear look which is able to allow sunlight to penetrate causing it to appear darker on satellite imagery.

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References

Aber, J.S. Remote Sensing . ES771 Remote Sensing. Emporia State University. 2007
http://academic.emporia.edu/aberjame/remote/lectures/lec09.htm

John Redmond Reservoir, Corps of Engineers. John Redmond Reservoir, Corps of Engineers. http://www.swt.usace.army.mil/projects/civil/civil_projects.cfm?number=18

Kansas Department of Wildlife and Parks. Coffey County Lake. http://www.kdwp.state.ks.us/news/fishing/where_to_fish_in_kansas/fishing_locations_public_waters/region_5/coffey_county_lake

Coffey County Chamber of Commerce. Map of Coffey County. coffeycountychamber.com/images/lakes.jpg