Integrating Past, Present, and Future Approaches - Spatial Mathematics: Theory and Practice through Mapping - page 233

information is in the roads table? The roads that are busy streets are those
with a CFCC2 code of A1, A2, or A3.
10.4.6 Putting it all together: Practice—Denver Internet café activity
Now that you have all the pieces completed, you are close to determining
the optimal site for your high speed Internet café in Denver. Putting those
pieces together will draw on mathematics and geography. Use the Analysis
Tools → Overlay → Intersect function to intersect areas within 1 kilometer of
the schools, colleges, and universities together with the block groups contain-
ing at least 10% of their population between 18 to 21 years of age. Name your
resulting intersection layer hs_univ_p1821 or something else that is suitable.
How many polygons are under consideration? There should be 1797 poly-
gons under consideration, but remember that these polygons are the result
of a spatial intersection function. Therefore, the polygons do not represent
block groups, but are small pieces from intersecting many disparate shapes,
including your buffer zones and block groups. Near which two universities
are these areas that are now under consideration for InstantWorld? The two
universities under consideration are Regis University on the northwest side of
Denver, and the University of Denver, in the south-central part of the city. The
University of Colorado-Denver (Auraria) campus is the third major university
in Denver. However, further investigation reveals that there are no neighbor-
hoods nearby with a high percentage of 18 to 21 year-olds. Can you speculate
why this might be the case? The reason is because this campus is a commuter-
based school, and there are no dormitories in or near the campus that would
largely house this age group.
It might be helpful for you to set a spatial bookmark at each of these locations
under View → Bookmarks → Create. Now you have combined, and thought
about, two of the three parts of the problem.
Recall that the final criterion is “on a busy street,” with a CFCC2 code of A1,
A2, or A3. Select these streets now. What expression did you use to select
these streets? Based on the discussions in this topic, you should know that you
need to select these streets with an “OR” operation, as follows: CFCC2 = A1
OR CFCC2 = A2 OR CFCC2 = A3. How many street segments meet this “busy
streets” criterion? The selection should result in 1134 out of 24,011 street seg-
ments selected.
The next selection that you need to perform is a spatial, not an attribute,
selection. This will result in the selection of areas that are near schools and
universities that also contain at least 10% of their population between 18 and
21 years old, that are also near busy streets. To do this, use the Select → Select
By Location function to intersect your hs_univ_p1821 layer (your “target”
layer) with the busy streets (your “source” layer), as follows ( Figure 10.14 ) .
Describe your result and indicate how many polygons are now selected in
the hs_univ_p1821 layer. The result is a slightly smaller set of polygons in the