Our local data sets are large files and can take more time to display than you care to wait. You can create separate subsets of a theme and save  it to your own directory, so that you not only save time but have copies of your own to modify and use (I don't want you editing the original data sets!).

There are two methods you can use. One is to select a portion of an existing shape file and convert that to a new shape file. The other is to clip an existing shape file by using another polygon shape file (like using a cookie cutter) to create a new shape file.  If you use the selection method, you will come out with entire features, e.g., entire parcels, or entire road segments, so some of these may extend beyond the area you want. If you use the clip method, all features are clipped at the border of the cookie cutter. This has the advantage of not including anything outside your area of interest but the disadvantage of chopping some features up which perhaps should not be chopped (e.g., parcels).

To create smaller subset themes of large themes using the selection method:
You can only create a subset theme  by selection one theme at a time, so you will have to go through these steps for each theme. To create a subset of a theme:

1. In the view legend, click on the theme that you want to have in your subset file - this makes this the active theme, so that all other actions (selecting, displaying, etc.) relate to that particular theme.

2. Select the features of that theme that you want to have in your subset file. You can use any of ArcView's selecting tools - to learn about these go to the Help menu in ArcView, choose Help Topics, click on the Index tab and type in "selecting" and in the resulting list choose "selecting features on a view". (The easiest way to select features is to use the "selecting box" - fourth icon from the right on the bottom row of view menu icons)

3. With only the features you want selected, go to the Theme menu and choose Convert to Shape File

4. When prompted with the file management dialog box, navigate to the drive and directory where you want to save this data, and give it a name.

5. You will be asked if you want to add this new shape file to a view - answer yes.

6. You can now delete the larger shape file from your view and work with the subset.

7. Repeat the above steps for every theme from which you want to create a subset theme.

To create smaller subset themes of large themes using the clip method:
To use the clip method, you will need to have a polygon shape file which will act as the "clipper" (the cookie cutter) in addition to the "clippee" shape files. This could be an existing file like watersheds - in that case, select the watershed which will be your boundary area, and then perform the clip as outlined below. If you don't already have a shape file to use as the "clipper", create one by choosing View - New Theme and creating a polygon theme (e.g., a simple square covering the area you want to clip) - see Creating a new boundary feature below. If using X-Tools, you can simply create a quick graphic on the screen, then choose X-Tools - Convert Graphics to Shapes.

Once you have a boundary file to use as the "clipper" file, load either the Geoprocessing extension (it comes with ArcView 3.1 and higher) or the X-Tools extension (from the Oregon Department of Forests).  Both have a clipping function. To load an extension, choose File-Extensions, and on the resulting list, scroll down until you find extension you want , then click on the box next to it and press OK. Once loaded, the Geoprocessing Wizard can be found under the View menu on the View Document. If you are using X-Tools, there will be an X-Tools menu item added to the View Document. Then you can use the Clip function of either extension - just follow the prompts carefully to select the "clippee" and the "clipper" shape files. Also be careful where you are putting the newly made files - by default they will be called something like "clip1.shp" and be placed in the C:\temp\ drive. Give them a better name and put them in your own folder. You will have to go through the clipping process one time for each shape file you want to clip.

To create a new boundary feature to use as a clipper file:

• From the View menu, choose New Theme
• For Feature Type, choose Polygon
• When prompted, navigate to the folder where you want this new theme to be (probably in e:\temp\yourfolder\) and give it a name like boundary.shp
• Notice a new theme is added to your theme legend, with a dotted line around it - this means you are in editing mode for that theme
• On the ArcView tool menu, go to the draw rectangle tool and click once to see your drawing tools for a new feature:
  The three polygon shapes in the middle are available to you - a rectangle, a circle, or an irregular polygon - choose any of these
• Draw the boundary of the area you are examining - if you make a mistake, you can delete it and start over. For help, go to the Help menu, and choose Help Topics - Contents tab - Creating and Using Maps - Creating and Editing Spatial Data - Creating a New Theme
• When you have a boundary polygon complete for your area, choose Theme - Stop Editing, and respond Yes when asked if you want to save your changes.