Background:
In this report we were tasked to create image functions that could be used later for remote sensing applications. The following images were created using the supplied content in the lab exercise. Using this images we were then takes with manipulating the data to create new images, area of interests, image fusions, enhancement techniques and mosaicking. All these images would create better area of studies for us or better applications that we could use to further our research in remote sensing.
Methods:
The first task was to create a area of interest by using the Erdas computing program we were able to select an area of the image Eau_claire_2011.img we were able to do this by selecting the raster tool and creating an inquire box which selected an area we wished to study further. We then created a subset of the image by using the tool create subset image. We were then able to save this data and create a new area of study based on our inquire box
Image Fusion was the next task. A new area of interest would not be usable if we could not see the area that we were working with. Unfortunately the AOI that we were interested did not have a good quality of spatial resolution. To create a better resolution we use a pan sharpen tool with two different images. The first image had a 30 meter resolution while the second panchromatic image had 15 meter resolution. We used the raster tool followed by Pan sharpen to create a resolution merge. This merge was used with the inputs known as multispectral image fusion to create a sharper image for a better AOI. We used nearest neighbor algorithm to give us the best resolution possible. After the image resolution was created we were able to have an AOI with great resolution.
Here we see the new sharp image on the bottom right
We were finally ready to create an image mosaic using mosaic pro. Mosaic pro allows us to take two images from separate parts of the world that only share certain parts of each other and merge them together in order to create a single map. To do this we open up mosaic and mosaic pro to create new window. We then inserted our data that we would like to merge together. When we have the two images that we would like to merge together we have to make sure the histograms match by selecting the overlap areas, this will make sure that the images fuse together in an overlap function. Finally we were able to run the model and create a new mosaic from our work. The new mosaic has a greater area of study and a better more complete image than what we would accomplish with mosaic express.
Mosaic Pro
The last part of the lab was to find the difference between two images taken 20 years apart. To do this we need the image from 1991 and 2011. We took the 2011 image and we built a basic model in model builder in Erdas imaging. The model subtracted the 2011 image from the 1991 image to find the differences between the two. We clarified this by looking at the histogram. Once we completed this function we needed to isolate the areas that have changed. To do this we used a conditional function EITHER IF OR OTHERWISE to use this function we said that there was either going to be a change above the change/no change histogram in the +/- range. If we had a change in this range it would be selected by the algorithm. After these algorithms have ran the course the data was then imported into ArcMap and a function map was created showing the following data.
Results:
The results of the mapping show that the areas that are marked in red are areas that have changed in the last 20 years. The results are interesting because we can see that the areas that have changed are not as we normally would have predicted. From the results we can see that the areas that were most affected were the urban areas. In the last 20 years urban development could have created these changes. These urban changes could be the result of buildings either being created or destroyed as well as other methods of infrastructure are being created. We can also see that red areas are in areas not designated as urban. these areas could be harvested by crops or we could be seeing trees being harvested as well as development in the country side which could include small houses or new farm fields being created and finally we could be seeing mines becoming more common in the country since frac sand mining has been a booming industry in the past 5 years or so.
