Creating and editing GIS data

Creating and editing GIS data CE 597 Spring 2011

Feature types in ArcGIS • Thematic collections of points, lines, or polygons • Line • Polygon Point

Feature types in ArcGIS Annotation Dimensions Multipoints Multipatches

Feature types in ArcGIS Dimension Multi-patches Multi-points Images: ESRI

Single-part/ Multi-part Single/multi –part lines Single/multi-part polygons

Vertices and segments • Segments may be straight lines, circular arcs, elliptical arcs, or bezier curves Image: ESRI • Vertices: Primary elements • Vertices may include • z-values: elevation • m-values: measurements along line features

Tolerance and resolution • XY tolerance: • minimum distance separating feature coordinates (e.g. 0.001 m) • used in clustering operations (topology validation, buffer generation, polygon overlay, clip, editing etc.) • XY resolution: • precision to store coordinate values • default: 0.0001 m

Editing basics Editor toolbar

Editing basics Editing tools are available only during an “edit session” (Editor > Start Editing, Stop Editing) Edits are temporary until saved permanently to the data (Editor > Save Edits) Saving the map document (*.mxd) doesn’t save the edits to the features !!

Editing basics • May edit data having different coordinate systems (best practice: editing data which have the same coordinate system) May edit data in a single folder or a geodatabase at a time May edit data of a single data frame at a time even if all the data in other data frames are in the same folder or geodatabase

Editing workflow • Select the workspace and data frame to edit • Start an edit session • Select the target layer to edit • Choose either to create new features or edit existing ones • Set up additional properties or options • e.g. snapping, setting selectable layers etc. • Select an editing tool • Add or edit attributes of the feature • Save edits and stop editing

Sketch tools Sketch tool

Sketch tools Sketch tool Intersection tool Arc tool Midpoint tool Endpoint arc tool Tangent curve tool Distance-distance tool Direction-distance tool Trace tool

Sketches point sketch polygon sketch vertex segment line sketch

Sketch tools vertex options general options Right click menu options

Snapping environment Snapping environment helps to establish exact locations with respect to other features May be used for generating, editing, or moving features

Snapping environment • Snapping tolerance • Editor menu > Options > General tab • Distance to snap a pointer or a feature within to another location

Snapping environment • Snapping environment dialog box • Editor menu > snapping Snapping properties Snapping priority

Snapping environment Snapping to a specific feature

Setting up units • Distance units • May choose while entering the distance using the unit’s abbreviation (e.g. km, m, ft, mi, yd) • Direction units • Editor menu > Options > Units tab

Tips: Setting selectable layers

Tips: Selecting the right feature Select a feature using the editor toolbar Switch to choose between possible selections within the tolerance to catch the right feature (by clicking N on keyboard)

Tips: Sticky tolerance Helps to avoid moving the features accidentally while editing them which may cause unintended gaps or overlaps Sets up a tolerance distance to start moving the feature Set from: Editor > Options > General tab

Tips: Where do I snap to? Activate snap tips to see where the snap will take place Editor > Options > General tab

Creating and editing GIS data