ArcGIS Route

Creating a Route in ArcGIS

(Thanks to Shannon Albeke for showing me how to do this)

Set up a geodatabase to store your route features

Create the geodatabase

In ArcCatalog, navigate to the folder in which you want to store all of your data (your network drive will be fine)
Right-click (in the right pane of ArcCatalog) and select New > Personal Geodatabase
Rename your geodatabase

Create a new geodatabase Feature Dataset

Still in ArcCatalog, double-click on your new geodatabase to view its contents (should be empty)
Right-click in the right pane (of ArcCatalog)
- select New > Feature Dataset (opens up a wizzard which steps you through the process)
  - enter a name for the new feature dataset, hit next
  - specify the projection information that will be used (I suggest UTM/Zone17 for eastern Georgia and UTM/Zone16 for western Georgia), hit next
  - leave the Vertical Coordinate System as <None> (unless you know it), hit next
  - use the default tolerances, hit finish

Import Features into your feature dataset

Still in ArcCatalog, double-click on your new feature dataset you just created (should be empty)
Right-click in the right pane (of ArcCatalog)
- select Import > Feature Class (I selected multiple which allows me to import >1 datasets as long as they're cast in the same projection)
- use the open dataset dialog to navigate to and load your data, hit OK when you're done

Now is a good time to open ArcMap and view your data. Close ArcCatalog and start a NEW ArcMap project. Load the features you just imported and do a visual check:

Do the data align? If not, you may have incorrectly defined or mis-specified projection.
Load some other data, are things in the right place? Again, if they are not, there is most likely something wrong with your data's defined projection.
Look at the attribute tables. Is the information that you need there? If not, now is the time to join or calculate the fields you'll need (UID's, recode dates and other identifiers, etc.)

Using the above methods, I've created 2 feature datasets in my geodatabase: 1) a river centerline, "RivCtr" and 2) a point dataset, "SmpPnt", that represents sample locations along the river. The edits I made to the data are as follows:

To SmpPnt:

added a unique id field - "uid" (1 - 375)
added a unique id field to denote sample month - "uid_month" (1 - 12)
added a unique fish id for each individual fish - "uid_fish" (textual)
added a unique fish/month id, "uid_fshmo" (textual)

To RivCtr

eliminated slivers, overshoots, and gaps
eliminated secondary paths so only the centerline of the main river remains
dissolved all lines, leaving a single arc (1 record)
added a unique id field - "RID"

Create the route

Load ArcToolbox (from ArcMap)
Select Create Routes (ArcToolbox > Linear Referencing Tools, or search for it)
- In the Create Routes dialog, enter the following:
  - Input Line Features: the line dataset
  - Route Identifier Field: UID field for the line feature
  - Output Route Feature Class: new feature class, store it in the feature class you created above
  - Measure Source: LENGTH
  - Coordinate Priority: specify the location of line feature's origin (does the flow start in the upper left, upper right, lower left, or lower right)
  - remaining entries, see below
- Hit OK when you're done

Locate sample points along the route

Load the Locate Features Along Routes tool (ArcToolbox > Linear Referencing Tools, or search for it)
- In the Locate Features Along Routes dialog, enter the following:
  - Input Features: the point features
  - Input Route Features: the route you created above
  - Route Identifier Field: UID field for the line feature
  - Search Radius: a tolerance value defining how far away a point can be from the route (if the distance is greater than the tolerance, then it is not considered)
  - Output Event Table: name of the new table that is generated, store it in the geodatabase you created
  - Route Identifier Field: UID field for the line feature
  - Measure Field: name of the field in the new table that will contain the route measurement values
  - remaining entries, see below
- Hit OK when your done

Click on the Source tab (bottom of the layer list in ArcMap) and open the table you just created.
The distance from the origin of the route to the current feature is stored in the "MEAS" field

Make a route event layer

Load the Make Route Event Layer tool (ArcToolbox > Linear Referencing Tools, or search for it)
- In the Make Route Event Layer dialog, enter the following:
  - Input Route Features: the route you created above
  - Route Identifier Field: UID field for the line feature
  - Input Event Table: name of the event table you just created
  - Route Identifier Field: UID field for the line feature
  - Event Type: POINT
  - Measure Field: name of the field that contains the distance measurements (default is MEAS)
  - Layer Name or Table View: name of the new layer that will be created
  - remaining entries, see below
- Hit OK when you are done

You should now visually inspect the layers we just created. Turn the route and the route event layers on and zoom in close to an area. The route event layershould be sitting on top of the route. Look at the event layer's attribute table. The "MEAS" field is the distance (starting at the origin of the route) along the route to that feature. The original attributes should be carried over too. Export this table as a dbf or text file for further analysis in your favorite stat package.

DONE!!!

What we did:

Created a geodatabase in which all of the data is to be stored
Created a Feature Dataset within the geodatabase
Imported our line and point feature datasets
Edited the data and their associated attributes
Created a route layer
Located events along the route layer
Created a new point layer showing those events

Warnell GIS and Spatial Analysis

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