Geography Reference
In-Depth Information
FIGURE 9-18
7. Open the Streets attribute table. Make it occupy the full screen. How many street segments
are there? ________. Notice that the field names suggest that this dataset was derived from
TIGER/Line files. Notice also that several fields have been added. You will see Full_Name,
street length in meters, FT_Minutes (some sort of average time for traversing the street,
moving from the from node (F) to the to node(T)), and TF_Minutes (same sort of thing, but
traversing the opposite direction). 22 Notice also the field Oneway, which contains either FT
(meaning traffic may proceed from the FNode to the TNode) or TF. Minimize or dismiss the
attribute table.
8. Choose Selection > Select By Attributes. Make the layer Streets. In order to find the
intersection of Pine and Fillmore Streets, create exactly the following query, being aware that
every character is case-sensitive:
“Full_Name” = 'Fillmore St' OR “Full_Name” = 'Pine St'
and press Verify. If it works, press Apply. Now choose Selection > Zoom To Selected Features.
9. Obviously, from all the selections you see, there are Pine and Fillmore streets scattered all over
the Bay Area. You are interested in the two that intersect, so zoom in on those. See Figure
9-18. Then, zoom in tightly on the intersection itself.
22 These two numbers might be used to indicate one-way streets (by making the “wrong way” a very large num-
ber), but the one-way issue is handled in a different way: by the field Oneway.
 
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