1. BY
B ANEESHA SATYA
131854

2. •GEOCODING
•APPLICATIONS OF GEOCODING
•DYNAMIC SEGMENTATION
•APPLICATIONS OF DYNAMIC SEGMENTATION

3. BASIC GIS FEATURE TYPES
• Point
- Cities, control points (BM), weather stations
- Location, distance (buffer), point pattern, interpolation
• Polygon
- States, land use (zoning), land cover, eco-region
- Location (area coverage), distance, shape metrics,
overlay
• Line
- Roads, streams, utility lines, path
- Location (linear referencing), distance, shape metrics
(e.g., sinuosity), connectivity

4. LINEAR FEATURE ANALYSIS :
• Linear referencing - location
- Geocoding (e.g., address matching)
- Dynamic segmentation
Geocoding - the process of assigning spatial locations to data
that are in table format but have fields that describe their
locations.
Dynamic segmentation – the process of computing the location
of events along a route, can locate spatial features (linearly
referenced events) from a data source that lacks x-, and ycoordinates.

5. TYPES OF GEOCODING
•
•
•
•
Address matching
Corner (intersection) matching
ZIP Code geocoding
Reverse geocoding

6. ADDRESS GEOCODING: plots street address as point features in a map.
Most common type is address geocoding (address matching) : Internet mapping
such as MapQuest, Google, Yahoo, MS’s
MapPoint…
Requires two sets of data such as street name, zip codes segmented data
-Individual street addresses in a table(one record per address)
-Reference database
Address geocoding interpolates the location of a street address by comparing it
with data on the reference database
A sample address table records name,
address, and ZIPcode.

7. GEOCODING REFERENCE DATABASE: consists of street map and
attributes for each street segment such as street name , address ranges, zip
codes
1.TIGER/Line files (U.S. Census Bureau)
-Contain legal and statistical boundaries, streets, roads, streams,
water bodies
- Has Built- in topology
-Also contains attributes for each street
2. Segment street name, beginning and ending address numbers on each
side, ZIP codes on each side
3. Also available from commercial companies like Tele ATLAS
The TIGER/Line files include the attributes of FEDIRP, FENAME, FETYPE,
FRADDL, TOADDL, FRADDR, TOADDR, ZIPL, and ZIPR, which are
important for geocoding.

8. GEOCODING PROCESS:
-GIS software packages have built-in geocoding engines for
address matching(ARCgis ,Mapinfo)
-Two steps
•Pre processing-breaks address into segments
EX:620 N
• Software first locates street segment in reference database that
contains the address.
- Then it interpolates where the address falls within the address
range and gives a point location.
Linear interpolation for address geocoding.

9. ERRORS IN ADDRESS RECORDING
- Misspelling of street name
- Incorrect address number
- Incorrect direction prefix or suffix
- Incorrect street type
- PO Box type instead of street address
- Incorrect ZIP code

10. ERRORS IN REFERENCE DATABASE
-Outdated because it lacks information on new streets
-Street name changes
- Street closings
-ZIP code changes or incorrect ZIP codes
- Missing address ranges
- Gaps in address ranges

11. ADDRESS MATCHING OPTIONS
- Geocoding engine has provisions for relaxing the
matching conditions but uses a scoring system.
- User may decide the rigor or accuracy of address
matching
- Spelling sensitivity
- Acceptable hit rate
- Geocoding process converts addresses to points
- End offset and side offset options

12. •The end offset moves a geocoded
point away from the end point of a
street segment
•The side offset places a geocoded
point away from the side of a street
segment.
-point in polygon
analysis(linking point address to
census)

13. OTHER TYPES OF GEOCODING
-Intersection matching also called corner matching, matches
address data with street intersections
here end points of two different addresses in
intersection are matched
-ZIP code geocoding matches a ZIP code to its centroid
location
instead of using street network x,y coordinates are
used
-REVERSE geocoding converts location into descriptive
address
An example of Intersection matching.

14. GEOCODING APPLICATIONS
• Location based services (GPS, e911)
• Geodemographic analysis
• Public health
• Crime analysis
•Data preparation for spatial analysis
• Real estate
• Health services
• Travel times and distances (emergency response)
• Crime mapping and analysis00

15. DYNAMIC SEGMENTATION
• DS is the process of computing the location of events along
route. Should have a built-in measurement system
•Routes((multipart)polylines)-linear feature with linear
measurement system stored with its geometry.
Ex:Mileposts along highways, mileage
measurements along stream
•Sections (polylines)
•Events-linearly referenced data that occur along routes
Ex: Events include speed limit changes, traffic
accidents, fishery habitat conditions along streams
•Dynamic segmentation links events to the routes

16. ROUTES
- Must have built-in measurement system
-distinction in measurement system storage between ESRI’s coverage
model and geodatabase model
-Coverage model treats route as sub-class in a line coverage
- Geodatabase data model treats route as polyline feature
An example of a route subclass using
the coverage model
Fig a- arcs showing the linear features.
Fig b-route super imposed with linear
features.
Fig c- tabulates the linear measure of
three sections.

17. • Geodatabaase model treats a route polyline feature
class.
•Simply stores linear measures in the geometric model
• x,y values locate the linear feature in the coordinate
system ,m value relates to route’s linear measurement
An example of a geodatabase route
feature class.

18. Creating Routes
-Interactively or through data conversion
-Interactive method: first digitize route or select existing lines, then
apply measuring command to the route to compute route
measurements.
- Data conversion method: can create routes at once from all linear
features or from features selected from data query.

19. The interactive
method requires the
selection or
digitizing of the line
segments that make
up a route (shown in
a thicker line
symbol).
Interstate highway
routes in Idaho

20. ROUTE TYPES
- Simple route :one direction, no loop or branch
-Combined route : joined with another route, has different
conditions depending on direction.
- Split route : subdivided into two routes
- Looping route : intersects itself
An example of a split route.

21. Events
-Linearly referenced data usually stored in a table
- Dynamic segmentation process is independent of x-, ycoordinate system
- Events may be point or line events
Point Events
-Accidents, stop signs
- Occur at point locations
- To relate point event to a route, point event table must have route ID, location
measures of events, and attributes describing the events

22. Line Events
- Pavement conditions
-Cover part of a route
-To relate line events to a route, line event table
must have route ID, and from and to measures.

23. CREATING EVENT TABLES
-Two common methods
- Create event table from existing table n Method assumes that event data are
present in tabular form and linear measures are available
- Create table by locating point or polygon features along the route
- Similar to vector-based overlay operation
- Input layers are a route layer and a point or polygon layer
- Instead of creating an overlay layer, a table is created
An example of converting
point features to point
events.

24. An example of creating a
linear event table by
overlaying a route layer and a
polygon layer

25. APPLICATIONS OF DYNAMIC SEGMENTATION
-Dynamic Segmentation can store attributes along with routes which can
then be displayed, queried, and analyzed
-Useful for data management, data display, data query, and data analysis

26. Data Management
-Useful in two ways
- Different routes can be built along the same linear feature
- Different events can reference the same route, or, more
precisely, the same linear measurement system stored with
the route
- Fisheries biologists can store various environmental data
with a stream network for habitat studies.

27. Data Display
- Once table is linked to route, table is georeferenced and
can be used as a feature layer.
- Similar to geocoding an address table

28. The thicker, solid line symbol represents those portions of the
Washington State’s highway network that have the legal speed limit
of 70 miles per hour.

29. Data Query
-Can perform attribute data query and spatial data query on an
event table and its associated event layer
- Recent traffic accidents follow pattern
Data query at a point, shown here by the
small circle, shows the route-ID, the x- and
y-coordinates, and the measure (m) value at
the point location. Additionally, the
beginning and ending measure
values of the route are also listed.

30. Data Analysis
-Routes, events may be inputs for analysis
-Efficiency of public transit routes
- Buffer the route, overlay with census blocks and
demographic data for planning and operation of the public
transit system
- Data analysis between two event layers
- Relationship between traffic accidents and speed limits
(similar to vector-based overlay operation)