Working with shapefiles Shapefiles are Arc Views file

Working with shapefiles • Shapefiles are Arc. View’s file format • Each shapefile is a collection of files. shp -- spatial data (shape geometry). shx -- spatial data index. dbf -- attribute data • What you can do with shapefiles Convert an existing theme to a shapefile Create a new theme based on a shapefile Edit shapefiles

Creating a new shape theme • • Create new theme and specify feature type Name theme

Creating a new shape theme • Shape theme is added to the view • New theme is active and ready for editing

Adding shape theme features • Use the Draw tool to create new features Point Line Multiline Rectangle Circle Polygon Line split Polygon split Auto. Complete

Adding attributes • New theme table 1 record for each feature • Add fields • Add values

Saving your edits • During an edit session Save Edits As • After edits are completed Stop Editing Start editing another theme Save Project Exit

Editing shapefiles • • • Start/Stop Editing Select features Reshape features Snap features Split features Modify features Union Combine Intersect Subtract

Editing polygon themes • • • Delete polygon features Cut and paste polygon features Move polygon features Resize polygon features Reshape polygon features Split polygon features Merge polygon features Create doughnut polygons Remove area of overlap between polygons Obtain the intersection of polygons

Reshaping features • Reshape a single polygon Click inside polygon Click to add vertex Drag to move a vertex • Reshape a common boundary Click on common boundary Click to add a vertex Drag to move a vertex

Snapping features • Connects features or vertices to existing features or vertices • Two types of snapping: General snapping Interactive snapping

Setting snapping • By typing a tolerance - Turn snapping on - Specify distance • Using the mouse (Click the right mouse button)

Splitting lines and polygons Single line Single polygon Split New lines (4) New polygons (2)

Updating attributes with Split • Set Split rule for each field • Before split • After split

Merging features with Union • Adjacent polygons 2 polygons, 2 records • Non-adjacent polygons 2 polygons, 2 records • Overlapping polygons 2 polygons, 2 records

Updating attributes with Union • Set Union rule for each field • Before Union • After Union

More editing operations • Combine • Intersect • Subtract (top) (bottom)