Introduction to ArcGIS for Environmental Sciences Day 2 – Fundamentals Module 8 Creating & Editing Data Creating Metadata

1 Introduction to ArcGIS Chapter 8 Objectives Describe Steps in Editing Process Move and Delete Features Edit the Shapes of Line and Poly features Create New Features by Digitizing Edit Feature Attributes Create Metadata

2 Introduction to ArcGIS EPA Examples of Creating and Editing Data Improving facility locations Delineating site boundaries Illegal filling of wetlands Landfill expansion Mapping unregulated facilities to conduct inspections (GW Compliance) Mapping permits not regulated by EPA to evaluate cumulative impacts (Env. Review)

3 Introduction to ArcGIS Editing Feature Shapes When editing the shape of a feature, you work with its sketch The sketch represents the geometry of a feature Segments Vertices When you edit a feature’s shape, you primarily modify the features vertices You can move, insert or delete vertices Editing the vertices will affect the segments Changes you make to one feature’s shape may affect the shapes of other features if they are spatially related.

4 Introduction to ArcGIS The Editing Process 1. Add the data you want to edit to your map Add other layers for orientation and reference (e.g., aerial photography) 2. Display the Editor toolbar and start an edit session 3. Set the editing environment Specify your editing target – the layer you want to edit Specify the editing task (e.g., modify) Enable additional settings (e.g., snapping) 4. Select the feature and display its sketch Double-click a feature to show vertices and segments 5. Make your edits Move, insert or delete vertices 6. Save your edits Changes are not updated until you save your edits – save often

5 Introduction to ArcGIS Creating New Features - Digitizing Heads-up digitizing – tracing shapes on screen using another layer for reference (aerial photos) Each time you click on screen, an x,y coordinate is recorded To digitize, follow these steps: 1. Start an edit session and set editing env. (target layer, editing task and snapping environment) 2. Zoom to the feature you want to digitize on your base layer 3. Trace the outline of the feature, clicking to create each vertex 4. Save your edits

6 Introduction to ArcGIS Editing Made Easier with Snapping Snapping is used to make sure features connect properly with other features Setting the snapping environment involves: –Setting the snapping tolerance – distance within which a feature is snapped to another feature (Editor menu  Snapping  Options) –Setting snapping properties - vertices, edges or endpoints (Editor menu  Snapping  Snapping Toolbar) –Specify the snapping priority - order of which layers get snapped to (Editor menu  Snapping  Snapping Toolbar)

7 Introduction to ArcGIS Maintaining Spatial Relationships - Topology If two features are adjacent, connected or coincident with each other, editing the shape of one will change the other’s shape as well. Examples: –Two adjacent land parcels –Roads and bus routes are coincident –Streams must remain connected To maintain spatial relationships in ArcGIS, you can setup a map topology during an edit session. A map topology defines spatial relationships among features and maintains them during editing.

8 Introduction to ArcGIS Editing Feature Attributes Follow the same process used for editing feature shapes Start an edit session Select the features you want to edit Make the edits Save the edits

9 Methods of Editing Attributes: The Attribute Dialog Box Displays the attribute values of the selected features in the map You can edit individual feature attribute values by typing, copying & pasting, or deleting You can also make changes to all the selected features at one time Introduction to ArcGIS

10 Introduction to ArcGIS Methods of Editing Attributes: The Attribute Table Manually edit feature attributes by typing, copying & pasting, or deleting Use the Field Calculator to automate editing

11 Introduction to ArcGIS Calculating Attributes with the Field Calculator Available from the layer attribute table Enter an expression that calculates values for selected features Calculate values for numeric, text and date fields Create expressions based on values in other fields

12 Introduction to ArcGIS XTools Pro: Calculating Area, Perimeter, Length, Acres and more Xtools Pro extends ArcMap and ArcCatalog's capabilities and streamlines many common data management functions Editing Functions include certain table operations, data management and editing options Under EPA’s corporate license, Xtools Pro can be installed on any EPA machine that has ArcGIS installed Download from the Office of Technology Operations and Planning (OTOP) web site. Download from the Office of Technology Operations and Planning (OTOP) web site.

13 Introduction to ArcGIS Metadata Whenever you obtain/create data, you should also obtain/create metadata Metadata – a document that describes your data Contains information like: –Who created the data –Who is the point of contact –When were the data created –Description of the data (abstract, purpose, etc.) –Data quality (accuracy, completeness, coverage, etc.) –Use and access constraints –Confidentiality –How the data were processed and who did the processing –Attribute definitions –Distribution information and liability

14 Introduction to ArcGIS Metadata: Why is it so important?

15 Introduction to ArcGIS Metadata: Why is it so important?

16 Introduction to ArcGIS Without metadata, you don’t know much about the data except what the title tells you (sometimes something is better than nothing) Without metadata, you have to take the data at face value –probably not defensible in court –this has been a problem with some imagery services Without metadata, data can easily be misinterpreted by users, resulting in erroneous maps Data may not even be usable without certain metadata like projection information or definitions for attribute codes Metadata: Why is it so important?

17 Introduction to ArcGIS Creating Metadata EPA Metadata Editor (EME) –Developed as an alternative to ESRI’s Metadata Editor –Much easier to use –Drop-down menu options –Default settings –Links to help files –Color coded items indicate whether they are optional or mandatory to pass EPA and FGDC metadata standards –Ability to edit Access database with personal contact information Access to EME is from ArcCatalog Download EME from EPA’s National Geospatial Program web siteEPA’s National Geospatial Program Other Tools for Creating/Editing Metadata –ArcCatalog –XTools Pro

18 Introduction to ArcGIS EPA Metadata Editor (EME) Basic Data Set Information (Tab 1)

19 Introduction to ArcGIS EME Quality, Coord. System and Attribute Info. (Tab 2)

20 Introduction to ArcGIS EME Distribution & Metadata Information (Tab 3)

21 Introduction to ArcGIS Final Words on Metadata Important to document key points of data: –abstract –attribute definitions –limitations/quality –projection –point of contact