1. I need to create 1 kilometer buffers around point locations of Burlington houses (some of which might only be several meters apart). When finished, I would like to be able to select the buffer polygon for a specific, individual house. What value should I specify for the “Dissolve Type” parameter when I run the Buffer tool?
2. What is the purpose of the “Dissolve Type” parameter in the Buffer tool?
3. Defining data types is an important part of designing the structure of an attribute table (the “database” part of a GIS dataset). Understanding those data types hedolps us to query features based on their attributes.Here is part of the attribute table of a dataset containing polygons that are simple shapes.
4. Match the geoprocessing tool with the category to which it logically belongs.
A. Tools that reduce the size of the minimum mapping unit, breaking features down into smaller features
B. Tools that aggregate features, increasing the size of the minimum mapping unit
C. Does not break features down or aggregate them but creates new features
5. Recall that spatial analysis is possible, in part, because of vector topology. In the vector data model, polygons are composed of lines, which are themselves composed of vertices and nodes connected by line segments. Consider the mock, vector dataset below composed of polygons. Answer the 2 questions below by entering the correct number.
The heart shape is not hiding part of the square but is embedded within the square. The minimum number of nodes in the square polygon is .
The minimum number of nodes in any of the other polygons in the shapes dataset above (excluding the square) is .
In this set of questions, name the geoprocessing tool that will do what is being requested. Each question has accompanying figures below the question. (In all cases, the answer is only one or two words, which need to be spelled correctly).
6. In Figure 1 below, the polygons represent Superfund cleanup sites, the line is a stream and points are wells. To create polygons representing 100 meter setbacks around the streams and wells (as shown in figure 2), one would use the tool.
Next, we would like to create a layer that combines the well setbacks and the stream setback layers (figure 3) into a single layer (figure 4). The tool will accomplish this task.
Now that all of the setback areas are in a single layer, the tool can be used to eliminate all internal borders as in figure 6 below.
Finally, let’s overlay the layer of setbacks (figure 6) with the superfund layer to show only polygons representing areas within Superfund sites that are also within setbacks. In other words, create areas that are common to both layers (figure 8). The tool will perform this overlay for us (there are 2 correct answers).
7. The 4 wetland datasets shown in ArcMap (figure below) can be assembled into a single, new dataset containing wetland polygons from all 4 tiles by using the tool.
After assembling the 4 tiles into a single dataset, I could run the tool to get rid of the tile boundaries (the straight lines defining each input dataset’s borders that are not actual wetland boundaries).
8. Write two attribute queries as specified below using this dataset containing simple polgyons as shown in ArcMap.
Write an attribute query that you would use in the interface below to select the heart polygon.
Write a second query to select rectilinear shapes that are larger than average, which is 110,000,000 square meters. Note that this is a multiple-attribute query.
Be careful with syntax. The figure below (or an actual ArcMap session) will help you write the syntax correctly.
9. Select a geographic question that can be answered by performing a spatial join of two layers (question and data can be fictitious, but keep it reasonable). Describe the spatial join process for this question. Be sure to provide these details:
• the cardinality (one-to-one or one-to-many) of the join (i.e., simple or summarized),
• whether it is an inside or distance join, and
• which data layer is the “To” layer (the one you would right-click in ArcMap to set up the join).
Spatial Joins are complicated. It is totally OK if you get it wrong the first time. Someone will help you out. Make your first post by the end of the day on Wednesday.
Comment (substantively!), question or assist in at least 2 other student’s posts by the end of the week… or, propose an alternative analytical approach that might be more appropriate or informative (this part will be easier after we get into module 7).