Digitization in ArcGIS

Digitizing in GIS is the process of converting geographic data either from a hardcopy or a scanned image into vector data by tracing the features. During the digitzing process, features from the traced map or image are captured as coordinates in either point, line, or polygon format

1. DIGITIZATION
Mashhood Arif

2. Outline
Digitizing overview
GIS features
Digitizing features
Advanced digitizing tools
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GIS TUTORIAL 1 -Basic Workbook

3. DIGITIZING OVERVIEW
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GIS TUTORIAL 1 -Basic Workbook

4. Why digitize?
New maps
Map features are wrong
Missing features
Other?
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GIS TUTORIAL 1 -Basic Workbook

5. Digitizing tablets
Used to digitize hard
copy maps into GIS
Transform wire
intersections into
coordinates of the
tablet’s coordinate
system
Heads down digitizing
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GIS TUTORIAL 1 -Basic Workbook

6. Steps for heads down digitizing
Tape map to the
digitizer
Register control points
on the map
Estimate two
conversion equations
(one for vertical and
one for horizontal
coordinates)
Digitize vectors (points,
lines, or polygons)
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Control
points
Map
Puck
Tape

7. Heads up digitizing
Mouse on a screen
Digitizes paper maps, aerial photos, or other
images
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8. GIS FEATURES
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GIS TUTORIAL 1 -Basic Workbook

9. Points
Single features
Nodes
Line endpoints
Vertex points
Controls shapes of lines
and polygons
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GIS TUTORIAL 1 -Basic Workbook

10. Creating points
Heads up digitizing
Single point features
Sketch tool and snapping features
Points added as XY event files
Points geocoded using addresses
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GIS TUTORIAL 1 -Basic Workbook

11. Lines
Starting and ending points with shape
vertices as needed
Vertex points
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GIS TUTORIAL 1 -Basic Workbook

12. Lines
Physical attributes of TIGER streets
Shape
From and To attributes
Node
Address
Lat/long
Length
GIS TUTORIAL 1 -Basic Workbook
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13. 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)
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14. Polygons
Physical attributes
Shape
Area
Perimeter
Length
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GIS TUTORIAL 1 -Basic Workbook