Clipping a Grid or Raster Data Layer in ArcGIS

1. Open up a new ArcMap document and then click the “Add Data” button. Add the grid or raster data that will be used as the input layer in the clipping process. Also add the polygon shapefile that will be used as the clip layer in the process.
2. Next we will convert the raster data layer to a shapefile using the Spatial Analyst toolbar. First make sure the Spatial Analyst toolbar is added to the map window. Once it is added, open up the Spatial Analyst menu and select “Options”.
3. In the “Options” window click the Extent tab. Then open the “Analysis Extent” scroll box and select Same As Layer “(Your polygon layer)”. Then click OK. 
4. Open up the Spatial Analyst menu again and click on “Convert” and then “Raster to Feature”. With the “Raster to Features” window open select the grid layer as the “Input Raster”, select a unique field (a field that distinguishes each type of data in the table) as the “Field”, and select Output Geometry Type as “Polygon” and make sure the generalize lines box is checked. Also make sure your destination folder and file name are correct. Then click OK and when prompted add the new shapefile to the map window. When this new shapefile was created, though, only the field that you selected in the “Field” scroll box was added to the attribute table. You now need to add the rest of the fields to your new shapefile.
5. Right-click on the grid layer in the table of contents and click “Open Attribute Table”. Then click the “Options” button at the bottom of the window and click “Export”. Make sure the destination folder and filename are correct and click OK. Then click the “Add Data” button, navigate to the folder where your new table is stored and add the table to the ArcMap window.
6. For the last step we will join the new table to the new shapefile. Right-click the new shapefile in the table of contents and scroll down to “Joins and Relates” and then click on “Join”. In the Join Data window make sure the “What do you want to join to this layer?” scroll box says Join attributes from a table. Also make sure the new table that you just created is present in the “Choose the table to join to this layer” scroll box. Then choose “GRIDCODE” as “the field in this layer that the join will be based on.” Also choose the unique field (the same unique field that was selected in step #4) for the field in the table to base the join on. Once everything is ready click OK. Both the new shapefile and the new table are now joined. To create the final shapefile right-click on the new shapefile, scroll down to “Data” and then click “Export Data”. Make sure the “Export” scroll box says All features and that “Use the same Coordinate System as this layer’s souce data.” is checked. Also make sure that your destination folder and file name are correct. Then click OK and the procedure is finished.

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