Lab exercise 8 due Mar31, 2008

EES6513: Advanced GIS, UTSA

Student name: ______________

Part I: Get Start with Geoprocessing

Based on tutorials found in ESRI Visual Campus (campus.esri.com), "Geoprocessing with ArcGIS Desktop”

Lab data: Copy the directory of Lab 8 (Start, Prepare) under \\129.115.25.240\XIE_misc\EES6513\

into your local computer

Objective:

· Use ArcToolbox™ to manage geoprocessing tools

· Find the appropriate geoprocessing tool for a task

· Run a geoprocessing operation using

• a tool dialog box
• the command line
• a model
• a script

Step 1: Explore ArcToolbox

Start ArcMap and open ArcToolbox

If necessary, click the Show/Hide ArcToolbox Window button to display ArcToolbox. In ArcToolbox, you should see a group of toolboxes, like those shown below. If you are using ArcInfo and have ArcInfo Workstation installed, you will also see the Coverage Tools toolbox.

These toolboxes contain the tools that you will use to carry out all of your geoprocessing operations. You will be working with them (most of them in the analysis tools) throughout the rest of the course.

You have been familiar with part of these geoprocessing tools in the previous lab from the tool's dialog box. Now you need to learn how to manage your toolbox.

Step 2: set geoprocessing options

Start ArcCatalog. From the Tools menu, choose Options, click the Geoprocessing tab. The options that you set on this tab apply to all subsequent geoprocessing operations in ArcMap and ArcCatalog.

Check Overwrite the outputs of geoprocessing operations and Log geoprocessing operations to a history model.

Click the General tab. For top-level Catalog entries, scroll down the list and check Toolboxes, so that the system toolboxes will be displayed in the Catalog Tree. Uncheck the box for Hide file extensions, found at the bottom of the dialog box. Click OK to close the Options dialog box.

Right-click an empty area inside ArcToolbox. Point to Save Settings and choose To File, navigate to your …\Lab8 folder and name the file standard.xml. Click Save.

You have now saved the current state of ArcToolbox, as well as the current geoprocessing environment settings and any variables that may have been created in the command line as an XML file.

As you modify ArcToolbox in the coming steps, you do not need to worry about making irreversible changes. When you have completed the module exercises, to return to the standard configuration, simply right-click, point to Load Settings, click From File, and navigate to the standard.XML file you just created.

Step 3: Match ArcToolbox settings in ArcCatalog and ArcMap

Within an ArcGIS Desktop session, any changes you make to ArcToolbox in ArcCatalog will not automatically display in ArcMap. To match the ArcToolbox settings in ArcMap or other ArcGIS Desktop applications with those in ArcCatalog, you have three choices:

1. Close ArcCatalog before opening another ArcGIS Desktop application (ArcMap, ArcScene™, or ArcGlobe™). When ArcCatalog closes, the current state of the ArcToolbox Favorites tab becomes the default state for all ArcGIS Desktop applications. However, if you modified the environment settings or created any command line variables, they will not be saved. On the other hand, if you make changes to the Favorites tab in ArcMap or other ArGIS Desktop applications, they will not be saved unless you save the application's document (.mxd, .sxd, .3dd), in which case the changes are preserved for that document only.
2. Save the ArcToolbox settings as the default in any ArcGIS Desktop application, then open another ArcGIS Desktop application. This will preserve your environment settings and command line variables.
3. Save the ArcToolbox settings to a file in any ArcGIS application. Open another ArcGIS Desktop application and load the ArcToolbox settings from the file. This will also preserve your environment settings and command line variables.

In the previous step, you saved the ArcToolbox settings to a file. Now you will load those settings into ArcMap.

Right-click an empty area inside ArcToolbox, point to Load Settings, and choose From File. In the Load Settings dialog box, navigate to your module folder, and select Standard.xml.

Step 4: Create your own toolbox

Right-click an empty area of ArcToolbox and choose New Toolbox. Change the name of the new toolbox to Lynx_Tools.

After you create your own toolbox, you can copy your favorite tools into it for your particular project.

Expand the Analysis Tools toolbox-> Extract, right click Clip and choose Copy. Then right-click the Lynx_Tools toolbox and choose Paste. You will add more tools into your own toolbox later.

In the Catalog Tree, expand the Lynx_Tools Toolboxes folder, your can see your clip tool you create, and add more tools in it. You also can remove any tools you create.

Step 5: run a tool from the command line

On ArcCatalog, Click the Show/Hide Command Line Window button to display the Command Line window.

The top part of the Command Line window is the command line. The bottom part is the message area, where messages display when you run a tool.

Like the ArcToolbox window, the Command Line window can be docked (right) or be a free-standing window (left). You might prefer docking the window to the bottom of the ArcCatalog window. You can also resize the command and message areas.

In the command line (Only tools that are in ArcToolbox can be run from the command line.), start typing the word buffer.

A list of possible commands displays and there are three or two Buffer tools, select Buffer_analysis. This is the one you want for this exercise.

Make sure Buffer is highlighted and then press the space bar on your keyboard to insert the Buffer tool in the command line.

After the tool is inserted, usage displays above the command line, which contains command line syntax for the tool. In this case, you are commanding the software to buffer some features that you specify, thus creating a new feature class that you specify, by using a buffer distance that you specify.

Essentially, these are the same parameters that you saw when you ran the Buffer tool using a dialog box.

Note: Required parameters appear between the <> symbols, and optional parameters appear between the {} symbols.

Set parameters:

You want to buffer features in the Springs feature class, so you will choose Springs as your first parameter value. You could type the path and filename in the command line, or you could drag and drop the feature class. You will do the latter.

In the Catalog Tree, navigate to your …\Start folder and expand the CentralFlorida geodatabase. Drag the Springs feature class and drop it in the command line.

The next required parameter, out_feature_class, is highlighted in the usage.

From the Catalog Tree, drag CentralFlorida.mdb and drop it in the command line. Now press the Backspace or left arrow key on your keyboard. Type \Zones500 (don't forget the backslash!) and press the space bar.

The last required parameter, buffer_distance_or_field, is highlighted in usage. Type 500 and press the Space bar.

Tip: By default, the distance units are taken from the spatial reference—in this case, meters. If you wanted to use different units, you would simply add them to the distance value and enclose both in single quotes (e.g., '500 miles').

Now you will set your optional parameters:

Since you are not creating line features, you will accept the default value for line side. To indicate this, simply enter a pound sign (#) and a space.

You will also accept the default value for line end type. Enter another pound sign and another space.

For the dissolve option parameter, double-click ALL from the drop-down list to add it to the command line.

All of the necessary parameters have been set, so the tool is ready to run.

Tip: An explanation of command line syntax is available in the help document for each tool, accessible by right-clicking the tool in ArcToolbox and choosing Help.

Run the Buffer tool

With your cursor still in the command line, press the Enter key on your keyboard to run the tool.

As the tool runs, processing messages are displayed in the bottom part of the Command Line window. These messages include information such as when the tool began executing, which parameter values are being used, and the progress of the tool's execution. Warnings of potential problems or errors can also be displayed here. You may need to resize the window or scroll up in the message area to see all of the messages.

If you like, navigate to the new Zones500 feature class in the Catalog Tree and preview its contents in the display window, or add it to the arcmap.

Run the tool again

Once you have run a tool in the command line, you can quickly run that tool again, modifying any parameter values as necessary.

In the message area of the Command Line window, the tool you just ran and its parameters are displayed in blue text.

Right-click anywhere in the blue text and choose Recall. The tool and its parameters are added to the command line.

Before you run the tool again, you will change the buffer distance and output feature class name.

In the command line, replace Zones500 with Zones650. Then change the buffer distance from 500 to 650.

Press Enter to run the tool. Once the process has finished, notice that the Zones650 feature class has been added to the Catalog Tree.

Tip: Until you close ArcCatalog, any tool that you run and its parameter values will be listed in the command line message area, and can be recalled to the command line. After the application is closed, the processes are logged to a history model in the History toolbox.

Step 6 Run tools in a model

In this step, you will use a model that allows you to run several tools in sequence. The model has been created for you. You will learn how to create your own models in part 3.

In the Catalog Tree, navigate to your …\Start folder and expand the CentralFlorida geodatabase. Preview the Conservation feature class. Of all the features in this feature class, only some represent land or wetlands within an aquatic preserve. Suppose that you would like to create two new feature classes; one that is composed of only those wetland features and another that represents a 500-meter buffer of them.

In the Catalog Tree, expand the ProjectTools toolbox.

The toolbox contains two system tools, a script tool (Clip All), which you will use in the next step, and a model named SelectAndBuffer. Like any other tool, a model must reside in a toolbox.

In order to accomplish your task, you could first run the Select tool to extract the wetland features from the Conservation feature class and then run the Buffer tool on the new feature class.

Or, you can run the SelectAndBuffer model, which strings these two processes together.

Examine the model

Before you run the model, take a look at it in ModelBuilder.

In the Catalog Tree, right-click SelectAndBuffer model and choose Edit.

You will use ModelBuilder to compose and edit models. This model contains two tools, Select and Buffer, that are represented as rectangles.

The model also contains three data elements that are represented as ovals, which are inputs and outputs for the tools.

The tools work the same in the model as they do when you run them using dialog boxes. The only difference is that in the model they have been connected together so that the output of the Select tool is the input to the Buffer tool.

In the ModelBuilder window, double-click the Select tool to open its dialog box. Notice that the appropriate parameters for the tool have been filled in. Features in the Conservation feature class will be selected and the output will be a new feature class named Wetlands. A query expression has also been built that tells the Select tool to only select features where the values in field NAME_A equal LAND OR WETLAND INSIDE AQUATIC PRESERVE.

Click Cancel to close the dialog box.

The parameters have also been set for the Buffer tool. Double-click the Buffer tool to open its dialog box and review the parameters.

Notice that Wetland, which was the output feature class of the Select tool operation, is used for the Input Features of the Buffer tool. The output will be a new feature class named Wetlands_Buffer. Notice also that the buffer distance has been set, as has the optional dissolve type. Click Cancel to close the dialog box.

Run the model

When you run a model, the tool being executed is shown in red. A progress window will also appear. It tracks the progress of the geoprocessing operations.

Tip: Whenever you have the Command Line window open, you will see that the same information displays in the bottom part of that window. On the ModelBuilder toolbar, click the Run button . When the model finishes running, close the progress window if necessary.

Hint: Even if you selected the option to automatically close the progress window when you ran a tool from a dialog box, you may have to select the option again for the model progress window.

Notice that the tools and the output data elements now have drop shadows. The drop shadows indicate that the model has been run.

Leave ModelBuilder open.

In the Catalog Tree, navigate to CentralFlorida.mdb and preview the two new feature classes, Wetlands and Wetlands_Buffer.

Delete intermediate data

Once you build and run a model, chances are that you are going to run it more than once. For example, in this case, you might want to create a different selected set or change the buffer distance, or both. Before you run a model again, you will need to do a little data cleanup.

In the ModelBuilder window, from the Model menu, choose Delete Intermediate Data.

The SelectAndBuffer model is now in a ready to run state once more. Notice that the drop shadows have disappeared.

Look at the Catalog tree and notice that the two feature classes, Wetlands and Wetlands_Buffer, have also disappeared.

If you had wanted to keep those feature classes but run the model with different parameters, you would have to change the name of the output feature classes for the Select and Buffer tools.

Step 7: Run a custom script tool

In this step, you will use a script to clip all of the feature classes in the CentralFlorida geodatabase to the Marion County boundary, and you will put the clipped feature classes into the MarionCounty geodatabase.

You will learn more about scripts later in part4. For now, you will just see what a script looks like and how to run a script tool.

Examine the script

In the ProjectTools toolbox. The Clip All script tool is based on a Python script named ClipAll.py, which is located in your GeoprocessingArcGISDesktop\Start folder. To run a script as if it's a geoprocessing tool, using ArcCatalog or ArcMap for example, the script must be added to a toolbox. The script (ClipAll.py) has already been added to a toolbox and is named Clip All. You will learn how to add a script to a toolbox later. The Clip All script tool can be run like any other geoprocessing tool.

In the Catalog Tree, right-click the Clip All tool and choose Edit.

Because the script was written in Python, the ClipAll.py script opens in the PythonWin application.

You can get an idea of what the script does by reading the comments written in the script (shown in green text). You'll learn more about how to read scripts in part3. When you have finished looking at the script, close Python.

Run the script tool

In the Catalog Tree, double-click the Clip All script tool to open its dialog box. In this case, the parameters for the Clip All script tool have not been filled in, yet.

For the Input Workspace, drag CentralFlorida.mdb from the Catalog Tree and drop it into the text box.

For Clip Feature Class, drag the Boundary feature class and drop it into the text box.

For Output Workspace, drag MarionCounty.mdb and drop it into the text box.

Click OK to run the script tool.

Notice that as the tool runs, the processing messages appear in the message area of the Command Line window as well as the progress window.

When the processing is complete, right-click MarionCounty.gdb and choose Refresh. Then expand the geodatabase to see the clipped files.

Now you have initial impression on the basic tools of geoprocessings: Dialog tools, command line, model, and script. You will continue to learn about Model building and Scripts writing in the next lab