Module 4 Ground Truthing and Accuracy Assessment

Our goal for this lab was to ground truth our LULC classification map from module 3 utilizing Google Maps earth view and its 3d pan/tilt/zoom features as well as street view feature which had much higher resolution than our original imagery.  I've included my overall approach to the project and my final map:

NOTES:

1.      Because of my previous work as a land surveyor and the need to use aerial imagery, Autocad, GIS and google earth/google maps I saved some google map searching time.

2.      Because I had made sure that my map projection and truthing shape file were in the NAD_1983_HARN_StatePlane_Mississippi_East_FIPS_2301_Feet projected coordinate system, the point I created were also in this system.

3.      By creating all the points and then using the identify feature set to display in degrees minutes and seconds, I was able to paste this information into the google map search field.

4.      This took me directly to where my point was located and I could use the earth view in conjunction with the 3d tilt/pan and zoom options to quickly identify the classification of my point.

5.      If it matched, I entered yes in the True_YN column during my edit session

6.      If it did not match, I entered no in the True_YN column and entered a more accurate classification in the New_Code column.

7.      After completing my ground trothing, I saved my edits, updated my legend and added an accuracy note with explanation to the final map.

8.      The majority of my initial mistakes from module 3 were in determining the wetland classification.  I knew that they should be comprised of either some sort of marsh grass or trees/mangroves, but it was very difficult to discern in the original imagery.  The google earth view was more helpful, but it was still difficult to discern as much of the area looked like mud flats. 

9.      I did a bit of additional research for that region to determine what the local forestry association described as the flora for these tidal wetlands.  The majority seemed to be varying types of marsh grass.  As that was not one of our specific provided codes I used non-forested wetland.  I think in this case, using a level 3 or 4 code would be more beneficial if actual detailed wetland information were needed.  I feel there may be some areas which are mud flats and oyster beds visible during low tide, but since I did not know at during what tide cycle the imagery was obtained I could not speculate as to the validity of this conclusion.