1 / 39

Creating and Managing Vector Datasets in ArcGIS: A Comprehensive Overview

This guide provides a detailed overview of creating and managing vector datasets in ArcGIS. It covers essential tasks such as unioning, merging, intersecting, and clipping polygons, along with adding and managing attributes. Additionally, it highlights digitizing techniques, including heads-up digitizing and the use of digitizing tablets. Key topics include the importance of snapping for accuracy, altering shapes of lines and polygons, and effective editing practices. With practical tips on saving and undoing edits, this resource is ideal for GIS professionals and learners.

stillman
Download Presentation

Creating and Managing Vector Datasets in ArcGIS: A Comprehensive 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. Creating Feature Datasets(vector data) ESRM 250/CFR 520Autumn 2009 Phil Hurvitz 2

  2. Overview • Unioning polygons • Merging polygons • Intersecting polygons • Clipping polygons • Adding attributes • Undoing edits • Saving edits • Digitizing • Creating vector data sets • Converting to feature class • Creating new datasets • Snapping • Altering the shape of lines and polygons • Splitting features

  3. tedious & detail-oriented work Digitizing • most common “legacy” method of getting data into a GIS

  4. y = 10 operatorclicks on or traces features x = 5 Digitizing tablet • How the digitizing tablet works coordinates are placed in database

  5. Creating vector data sets • ArcGIS supports creation & editing of vector data sets (shapefile & geodatabase = “feature class”) • Point • Line • Polygon • Data sets are completely editable • Coordinate data • Attribute data

  6. CAD data Converting to feature class • Any supported vector data set can be converted to feature class

  7. Converting to feature class • Any supported vector data set can be converted to feature class shapefile or gdb feature class

  8. Converting to feature class • Selected sets are converted

  9. select feature type Creating new datasets • New datasets can be created from scratch in ArcCatalog • decide in advance what feature type to represent the data

  10. Creating new datasets • New datasets can be created from scratch in ArcCatalog • specify coordinate system

  11. Creating new datasets: “heads-up” digitizing • Done completely on computer (no digitizing tablet), hence the term “heads-up”

  12. Creating new datasets • Create a road layer using a photo background

  13. Creating new datasets • New features can be created from tracing existing selected features

  14. Snapping • Snapping controls: • how features align during creation/editing • connections of lines (node placement) • completion of polygons • avoid overshoots/undershoots • avoid slivers or gaps

  15. Snapping • Snapping behavior controlled by the Snapping Environment dialog

  16. Snapping

  17. Snapping options • Interactive snapping options • Snap to an existing vertex • Snap to an existing line segment or polygon edge • Snap to an intersection of two or more lines • Snap to an existing line endpoint • Snapping can be layer-to-layer

  18. Snapping • Helps avoid these errors J. Lawler

  19. Altering the shape of lines and polygons • Topological editing: shared edges are all affected by edits

  20. Altering the shape of lines and polygons • Non-topological editing: only a single feature is edited

  21. Splitting (cutting) polygons • Polygons are split by a user-defined line

  22. Splitting lines • Lines are split at a specified location

  23. Splitting features • Geodatabase splitting policies • Attributes are handled by policies • Duplicate: values in new records are copied from the parent record • Geometry property (e.g., area, perimeter, length) automatically handled • Geometry ratio • based on geometry (e.g., percent of area)

  24. image from ESRI Splitting features • Attribute splitting (for geodatabase feature classes) is handled by policies

  25. Merging polygons select multiple polygons from the same layer original polygons are merged into a single new polygon

  26. Merging polygons • Attributes are handled by rules in the same way as splitting image from ESRI

  27. Merging polygons • Merging polygons: an example J. Lawler

  28. Unioning polygons • Similar to merge, but can combine features from > 1 layer

  29. Intersecting polygons like mathematical intersection spatial area as the "set" for intersection a new polygon from common areas

  30. Clipping polygons Option 1: discard the intersection

  31. Clipping polygons Option 2: keep only the intersection

  32. Clipping: an example J. Lawler

  33. Clipping: an example J. Lawler

  34. Clipping: an example • Landscape metrics calculated from clipped frog home range % forest 73 % ag 12 Ag dist 20 F-patch.s 60 A-patch.s 6 J. Lawler

  35. Adding attributes • Attributes need to be defined for new datasets • Fields are added; define • field name • data type • width • decimal precision

  36. Adding attributes • Adding & defining fields: note field names & data types

  37. Adding attributes • After fields are added, attributes can be updated

  38. Undoing edits • Edits can be undone in reverse order • Edits can be undone up to the previous save (or creation) • Once a dataset’s changes are saved, edits cannot be undone • It can be good to have a backup of the data created before an editing session

  39. Saving edits • Save EARLY and OFTEN • You are prompted to save edits when: • Dataset is closed for editing • Another dataset is opened for editing • Document is saved or closed • ArcGIS is closed

More Related