Module 4:Geometric Correction: Image to Map Rectification

Usefulness of Rectification process: Image rectification is a preprocessing operation that intent to correct the distorted or degraded image data hence creating a more reliable representation of the original scene. It involves geo referencing. The random distortions and residual unknown systematic distortions are corrected by analyzing the Ground Control Points (GCP) in an image and then accurately locating the known ground locations in the map. The image with unknown coordinate system can be projected into a known coordinate system. The transformation equations involved, inter-relate the geometrically correct coordinates and distorted image coordinates. Hence once this process is done, the distorted image coordinates for any map position can be precisely estimated.
Pitfalls in Rectification process: Locating GCPs identifiable in both the images and pinpointing the exact location can be difficult sometimes if the image is not very clear, making the entire process of rectification challenging and difficult.
For the lab in particular, it was somehow difficult to place the checkpoints initially, error was quite high but finally I got to place the check points and got an error of 3.1.

Module3: Thermal Infrared Image Interpretation

Roads: The roads in the picture look very bright. The warmer objects tend to appear brighter than the cooler objects in the aerial images. The roads being asphalt paved absorb more heat and remain warmer in the night compared to other objects which are cooler because there is no heat source (Sun) at that hour. It is dawn image (taken at 6:45 am) just around the sun rise time and hence cooler temperature. Roads are still warm that time because of its absorption characteristics mentioned above and hence appear bright.

Natural and man-made vegetation: The vegetation appears to be of different tones which depend highly on the moisture content of the soil and the leaves of the trees. Moisture in the moist soil keeps them cooler than the drier soil and hence some darker patterns whereas the moisture in the leaves retains heat for longer duration and being warmer it has lighter tone at some places. One can see the variations in the shades in vegetation.

Sidewalks & Patio: They appear of lighter tone. The main reason could be the material of which they are made. The material seems to absorb heat and hence remain warmer and therefore appears of the lighter tone.

Storage Sheds in backyards: They appear darker in the aerial image since at night/dawn there is no heat source and hence cooler temperature. Also, the material of which they are made does not seems to retain heat and hence are cold. Therefore they look darker.

Automobiles: Most of the automobiles (cars) appear dark in the image since there is no heat source (sun) at night and at dawn, the temperature just starts to warm up because of the sunrise but not yet heated up. Hence the cars are cold and appear darker. Although in some cars you can see hot spots which could be due to the heated engine (car may be running and just parked) so the front engine is heated and appears brighter even at the dawn/night.

Bright spots on many of the roofs: There are bright spots of many roofs explaining that there is higher radiant temperature over there than the surroundings. There is probably a heat source, it could be a heating system’s vent, a chimney, which is keeping the temperature warmer out there and looks brighter in the aerial image.

SPOT Analysis

The resolution for the panchromatic image looks much higher. The picture looks much clear as compared to the Multi spectral image. But at the same time it is easier to distinguish between the vegetation (red), built up areas and water (blue) in MSS which gives different color to each. The pan image is black and white and hence difficult to identify.

Exercise II: What can you see?

What problems you infer or identify in using type of Picture (attachment 2)?
The vegetation is in shades of red which makes it difficult to identify specific details or type of vegetation. It is difficult to pin point which is forest cover, grass land etc. The blue shades mostly look like built up area but to identify types of buildings etc is not easy. The major intersections and roads can be seen easily but smaller lanes and details are not easily noticeable.

Contour Map showing Mean Annual Preciptation

I used manual interpolation method for contour map. The minimum value of 45" and maximum value of 70" is used. The isohyet interval is 5 inches. The width of contour lines is 2 points.

Wind Farm Location in Great Lakes

The potential off shore wind farm location is near "Water intake crib" which is around 3-4 miles off from the NW of the downtown Cleveland,OH.
Reasons for selecting this location:
1. There is estimated wind power of class 3 to class 5 in offshore areas of Lake Erie. Prevailing northerly and westerly winds have a long, smooth fetch across Lake Erie which results in strong winter and spring winds, especially along the coastal areas [1].
2. Already a pilot project is being done in the selected location.
3. BERR criterias: a) The average winds on the lake Erie are the highest recorded in the state. The average wind speed in the location is 16.4 mph which is excellent for power generation(utility scale wind farms require average of 15.7 mph). Prevailing winds are Southwest [2].
b) There could be impact on aquatic organisms, fishes due to placing the wind turbines , electrical cables. But this would not be a long term problem according to the study by DLZ Ohio Inc., a subcontractor to JW Great Lakes .
c) The nearest dwelling is around 12 miles from the location which satisfies the noise and shadow flicker problem criteria in BERR. According to the BERR criteria for noise, if the turbine to receptor is between 200 & 300 m, then noise power level is less than 50dBA. Also, source noise level of wind turbine is between 100-106dBA[3]. As regards to the nearest port "Cleveland" is nearly 16 miles from the location.
d) It being a off shore site, landscape visual impact would not be a reason for concern.
Sources:
[1] http://rredc.nrel.gov/wind/pubs/atlas/chp3.html#lake
[2](http://blog.cleveland.com/pdgraphics/2008/09/large_01FGWIND.jpg)
[3] http://www.berr.gov.uk/energy/sources/renewables/planning/onshore-wind/noise/page18728.html

FlowMap

I used maximum line width of 40 points. I did not put the heading for the legend because of space constraint.