GIS4035 - Module 3 Lab - Land Use/Land Cover Classification

In this week's lab we continued learning how to interpret aerial photographs using various elements but took it another step further by then classifying the interpreted areas using the USGS Land Use/Land Cover Classification System.  This module again covered a large amount of information.   Wrapping my head around the text and supplemental readings was overwhelming.  Once I started the lab however I was able to let go of some of the details and depth of information and focus on a Level II classification of the provided image.   This one image assignment made it clear how enormous a task digitizing an image can be and the amount of detail that could be required.   As the lab assignment stated "we could spend all semester examining this one photograph."

Lab 3 - LULC Classification Of Features In An  Image From Mississippi

1.     First step was to open ArcCatalog and review the TIFF image that was provided for the lab assignment.  

2.     Second, was to create a new shapefile, also in ArcCatalog, and then to set its coordinate system to match that of the TIFF file.

3.     The previous week’s lab had us use the Drawing toolbar to create polygons and then convert the graphics to a feature shapefile.   This week we used the Editing toolbar to build the polygon features that would be contained in the shapefile. 

4.     I recalled only using the Editing toolbar one other time in a class last Spring so I had to refresh my snapping and vertices techniques as well as learn about the Trace option.

5.     Saving edits was the key not only after creating the feature but also after editing the attribute table for each feature.

6.     I used the clip option for several of the polygons where there was overlap or intersection.  I feel the clip option could have been better utilized when initially creating a plan on digitizing the various classes.   Since the residential and body of water sections were a majority of land use/land cover in this image, in retrospect I probably should have created those class polygons first.

7.     Because I did very little mapping in my last class (Python programming), I am having to get back into the mapping mode.   Working on this map legend helped refresh some of my skills.

8.     I figured out how to display the spatial resolution on the TOC after using ArcGIS Help for spatial resolution.   I did not figure out the best way to calculate or formulate a MMU (Minimum Mapping Unit) for this image.   I roughly chose an MMU of 1/8 of a mile or somewhere between 500-660 ft².