html5-img
1 / 38

Digitizing Overview

Digitizing Overview. Why Digitize?. New maps Map features are wrong Missing features. Copyright– Kristen S. Kurland, Carnegie Mellon University. Heads Down Digitizing. Digitizing table or tablet . Copyright– Kristen S. Kurland, Carnegie Mellon University. Heads Up Digitizing.

bryce
Download Presentation

Digitizing Overview

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Digitizing Overview

  2. Why Digitize? • New maps • Map features are wrong • Missing features Copyright– Kristen S. Kurland, Carnegie Mellon University

  3. Heads Down Digitizing • Digitizing table or tablet Copyright– Kristen S. Kurland, Carnegie Mellon University

  4. Heads Up Digitizing • Mouse on a screen • Digitizes paper maps, aerial photos, or other images Copyright– Kristen S. Kurland, Carnegie Mellon University

  5. GIS Features

  6. Points • Single features • Nodes • Line endpoints • Vertex points • Controls shapes of linesand polygons

  7. Creating points • Heads up digitizing • Single point features • Sketch tool and snapping features • Points added as XY event files • Points geocoded using addresses(chapter 7)

  8. Lines • Starting and ending points with shape vertices as needed • Vertex points

  9. Lines • Physical attributes of TIGER streets • Shape • From and To attributes • Node • Address • Lat/long • Length

  10. Polygons • Three or more lines joined to form a closed area • Single polygons or multipart features • (Hawaiian islands can be multiple polygons as one feature) 4 3 1 2

  11. Polygons • Physical attributes • Shape • Area • Perimeter • Length

  12. Digitizing Features

  13. Create new feature class

  14. Create new feature class • Add spatial reference information

  15. Create new feature class • Add new fields

  16. Create new feature class

  17. Digitize new features • 1.Create base map • 2. Add feature in ArcMap • 3. Start editing (Editor toolbar) • 4. Digitize feature • 5. Stop editing and save

  18. Create base map for digitizing • Vector features or raster images

  19. Add new feature class

  20. Add Editor toolbar • Customize, Toolbars, Editor toolbar

  21. Start editing • Editor, Start editing

  22. Begin digitizing

  23. Click point (tree) locations

  24. Stop editing • Editor, Stop editing

  25. Edit attribute data • Start editing, populate fields in table

  26. Advanced Tools

  27. Specify angle and length • Lines and polygons • Straight segment tool • Type length and angle

  28. Snapping tools • Snapping toolbar

  29. Trace tool • Good for complicated shapes • Editor toolbar, Trace tool

  30. Generalize tool • Creates features for use at small scales with less detail while preserving basic shapes • U.S. Census cartographic boundary files • City planning • rivers • Census TIGER water feature

  31. Smooth tool • Smoothes sharp angles in polygon outlines to improve aesthetic or cartographic quality • Smooth before • Smooth after

  32. Cut polygons • Creates two polygons from one original • Cut polygon tool • Polygon before • Polygon after

  33. Spatial Adjustments

  34. Spatial Adjustments • Transform • Rubbersheet • Edgematch Copyright– Kristen S. Kurland, Carnegie Mellon University

  35. Transforms • Convert data from one coordinate system to another. • Converts data from digitizer or scanner units to real world coordinates. • Shifts data within a coordinate system, such as converting feet to meters. Copyright– Kristen S. Kurland, Carnegie Mellon University

  36. Rubbersheeting • Geometric distortions commonly occur in source maps. • They may be introduced by imperfect registration in map compilation, lack of geodetic control in source data, or a variety of other causes. • Rubbersheeting corrects flaws through the geometric adjustment of coordinates. Copyright– Kristen S. Kurland, Carnegie Mellon University

  37. Edgematching • The edgematching process aligns features along the edge of one layer to features of an adjoining layer. • The layer with the less accurate features is adjusted, while the adjoining layer is used as the control. • Attribute transfer is typically used to copy attributes from a less accurate layer to a more accurate one. Copyright– Kristen S. Kurland, Carnegie Mellon University

  38. Spatial Adjustment Example • Hamburg Hall Building Drawn in CAD • Spatially Adjusted to Aerial Photo Copyright– Kristen S. Kurland, Carnegie Mellon University

More Related