Linear Referencing - Introducing Geographic Information Systems with ArcGIS - page 601

You have identified 30000030 in Some_Routes as a feature. Next, you will Identify it as a route, but you
have to add a button to a toolbar to do it.
8. Choose Customize > Add-In Manager > Customize > Commands. Find Linear Referencing in the
Categories list. Drag the Command “Identify Route Locations” to the end of the Tools toolbar,
where it becomes a button that will bring up a tool. Close the Customize window.
9. Make the Identify Route Locations tool active, and click at a random point along the selected
route. What is the maximum value of the Measure of the route? ________. What would you say
the minimum value was? ________. Of how many parts does the route consist? ________. Click
on different points of the route so you can determine, based on the Measure value, in which
direction (northwest or southeast) the Measure increases? ________. Dismiss the Identify
Route Location Results window.
Suppose that you know that a call box has malfunctioned at Measure 3.35. You want to find that point on
the map.
10. Click Find (the binoculars) > Linear Referencing. For Route Reference, pick Some_Routes. The
Route Identifier is, as always, ROUTE1. Click Load Routes. Pick the route that you have been
working with: 30000030. The Type should be Point. Put in the Location 3.35 and press Find.
Information about the route should appear in the bottom panel of the window.
11. Right-click the row containing 30000030. Flash the route. Flash the route location that was
found. Draw the route location. Label the route location. Click the Select Elements pointer and
place it over the route label; click once and pause. Drag the label around, noting that it is a call-
out box. Press Delete to remove the box. Select the drawn location by dragging a box around it;
delete the drawn location. Close the Find window.
12. Add the table accident.dbf as data from the Linear_Referencing folder. Open the table. How
many accidents are recorded? ________. With Table Options > Select By Attributes, select
the records with ROUTE1 = 30000030. 24 Show the selected records. How many are there?
________. Right-click the gray box to the left of one record, click Identify, and examine the
Identify box that comes up. Note that the record contains a MEASURE field that indicates the
position along the route where the accident occurred. Lots of other data about the accident is
also recorded. Close the Identify window.
13. Move the table around so that you can see the map, and particularly Route 30000030. Notice
that no points along the route where accidents occurred are shown. That's because the table is
just that: a table. To see the locations of the accidents, you can use the table to make a layer.
(This layer will exist only in memory and will go away once you close ArcMap, unless you save
the map. Of course, you may specifically save it as a layer file by right-clicking and choosing
save as LayerFile.)
14. Show all records in the table. With Table Options, choose Clear Selection. Close the table. In
the T/C right-click Accident. Choose Display Route Events. Set up the window so that it looks
like Figure 9-23. OK the window.
24 As mentioned before, sometimes a field name in a query is enclosed in square brackets and sometimes in double
quotes. It depends on what database management system is in use for the layer or table.