Clipping Data in ArcMap
This procedure will outline two methods for clipping data within ArcMap: using the select feature tool and clipping files based on a pre-existing boundary. To clip more than one file at a time, use the ArcView 3.2 Batch Clip tool or follow the steps outlined in the ACMLA Bulletin 125, page 18 for clipping multiple files in ArcMap.
- Run ArcMap and add a single data set that requires clipping. For this exercise
the DMTI street network will be clipped to isolate the Niagara Region.
Using the Select Feature tool to clip
- Zoom to the area to be clipped using the zoom tool .
- Click the select feature tool .
- In the map window, draw a box around the study area (in this case, the Niagara
peninsula). All of the roads encompassed within this box are now selected.
- To create a new shapefile, right-click on the layer name indicated in the
Table of Contents. In this case, right-click
"ONrds" and select Data>Export Data...
- From the Export Data dialogue box, choose:
- Export: Selected features
- Use the same Coordinate System as this layer's source data.
- Output shapefile or feature class:
- Use the browse button to navigate to a suitable directory to save
the file. (Students may save clipped data in the directory named "students"
on the Public Workstation.) Click Save when you have selected a location
and file name.
- Click "Ok" in the Export Data dialogue box to begin
the export process.
- When prompted to add the exported data as a layer, click "Yes".
- To de-select the road features choose Selection>Clear Selected Features.
- Turn off the original layer by clicking the check box in the layer listing
to the left of the map window.
Using a pre-existing boundary to clip
- Run Arcmap and add the file to be clipped and the boundary file to be used as the "clipper". This example used a regional boundary file from DMTI Spatial.
- Click the Select Feature tool ,
then click on the polygon representing the Regional Municipality of Niagara.
The border should be highlighted as in the image below.
- Click the ArcToolbox to access the various toolsets.
- Click the plus sign + beside Analysis Tools, then Extract. Double-click the "Clip" tool.
- The Clip dialogue box appears. From the dropdown lists, make the appropriate selections.
Input Features (the layer to be clipped): ONrds
Clip Features (the layer to use as the clipper): CANrmn
Output Feature Class (location and filename of the newly clipped layer)
- Click OK to begin the clipping process.
The resulting clipped roads layer is added to the map window.
To perform a batch-clip operation using ArcMap 9.1 see ACMLA Bulletin Number 125, page 18.
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