At this time turn on the “Topo24K” feature class and look for your quadrangle name. You instructor can help you find the general area. With the “Identify” tool find the object ID (FID) of your assigned quadrangle. Figure 2 displays the “Identify” output window for St. Elmo quadrangle – note that the “Quad_name” field of the “Topo24K” feature class has been turned on as labels. The “Identify” tool verifies that the feature ID (FID) of the St. Elmo quadrangle is 51041. We will use this value in a “Definition Query” to filter in just the St. Elmo quadrangle as a clipping polygon. Figure 3 displays the setup of the definition query (Feature Class Properties > Definition Query). Do the same for your assigned quadrangle – afterwards it should be the only quadrangle boundary displayed. Add the topo quad raster given to you to verify you have selected the correct quadrangle- you should see the USGS topographic raster fit inside the “Topo24K” boundary. You are now ready to extract the land use raster using the Topo24K feature class as a “mask” polygon. Open the toolbox and activate the “Spatial Analyst > Extraction > Extract by Mask” tool. Fill in the window dialog with the information as indicated by Figure 4. The output of the clip – “StElmo_2001” will be automatically added to your project. Turn off the “NLCD2001_LC_N30W087” feature class to verify that the clipping was processed correctly. Repeat the above process to capture the 2011 land use data into “StElmo_2011”. Step 4: Re-classify the Land Use Categories For our purposes the land use categories used in the original raster can be consolidated. At this time open the attribute table for the “StElmo_2001” land use feature class. We will consolidate the categories in the following way: Land_Cover Reclass_Value Reclass_Name Open Water 1 Open water Developed, Open Space 2 Developed Developed, Low Intensity 2 Developed Developed, Medium Intensity 2 Developed Developed, High Intensity 2 Developed Barren Land 2 Developed Deciduous Forest 3 Forest Evergreen Forest 3 Forest Mixed Forest 3 Forest Shrub/Scrub 3 Forest
At this time turn on the “Topo24K” feature class and look for your quadrangle name. You instructor can help you find the general area. With the “Identify” tool find the object ID (FID) of your assigned quadrangle. Figure 2 displays the “Identify” output window for St. Elmo quadrangle – note that the “Quad_name” field of the “Topo24K” feature class has been turned on as labels. The “Identify” tool verifies that the feature ID (FID) of the St. Elmo quadrangle is 51041. We will use this value in a “Definition Query” to filter in just the St. Elmo quadrangle as a clipping polygon. Figure 3 displays the setup of the definition query (Feature Class Properties > Definition Query). Do the same for your assigned quadrangle – afterwards it should be the only quadrangle boundary displayed. Add the topo quad raster given to you to verify you have selected the correct quadrangle- you should see the USGS topographic raster fit inside the “Topo24K” boundary. You are now ready to extract the land use raster using the Topo24K feature class as a “mask” polygon. Open the toolbox and activate the “Spatial Analyst > Extraction > Extract by Mask” tool. Fill in the window dialog with the information as indicated by Figure 4. The output of the clip – “StElmo_2001” will be automatically added to your project. Turn off the “NLCD2001_LC_N30W087” feature class to verify that the clipping was processed correctly. Repeat the above process to capture the 2011 land use data into “StElmo_2011”. Step 4: Re-classify the Land Use Categories For our purposes the land use categories used in the original raster can be consolidated. At this time open the attribute table for the “StElmo_2001” land use feature class. We will consolidate the categories in the following way: Land_Cover Reclass_Value Reclass_Name Open Water 1 Open water Developed, Open Space 2 Developed Developed, Low Intensity 2 Developed Developed, Medium Intensity 2 Developed Developed, High Intensity 2 Developed Barren Land 2 Developed Deciduous Forest 3 Forest Evergreen Forest 3 Forest Mixed Forest 3 Forest Shrub/Scrub 3 Forest