[6-1] analyzing spatial relationships - selection by location

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1 Geographic Information Systems (GIS) Selection  by Location [61] [6- 1] Fall –2010 –GIS Dr. Mohammad N. Alm a sri Sele cti on by Location 1 Dr. Mohammad  N. Almasri Select  by  Location Previously, you selected features according to their attribute values Now you will select features based on their location That is, according to their spatial relationship to other   features [6- 1] Fall –2010 –GIS Dr. Mohammad N. Alm a sri Sele cti on by Location 2 There are four types of  spatial relationships that can be used: distance, containment, intersection, and adjacency

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8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

http://slidepdf.com/reader/full/6-1-analyzing-spatial-relationships-selection-by-location 1/21

Geographic Information Systems (GIS)

Selection by Location 

[6‐1]

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location1

Dr. Mohammad N. Almasri

Select  by  Location

Previously, you selected features according to their attribute values

Now you will select features based on their location That is, according to their spatial relationship to other  

 features

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location2

There are four types of  spatial relationships that can be used: distance, containment, intersection, and adjacency

8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

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Select  by  Location

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location3

Distance  Containment Intersection  Adjacency

Select  by  Location

Completely  Contain

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location4

8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

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Select  by  Location

Completely  Within

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location5

Select  by  Location

Intersect 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location6

8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

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Select  by  Location

ArcGIS defines 11 spatial relationships,  each a variation on one of  the four types:

Intersect

Are within a distance of 

Completely contain

Are completely within

Have their center in Share a line se ment with

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location7

  Touch the boundary of 

Are identical to

Are crossed by the outline of 

Contain

Are contained by

Intersect 

Intersect is the most generic

As its name implies, it will return any feature that geometrically 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

shares a common part with the source (reference) feature (or features)

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8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

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 Are within a distance of 

The  Are within a distance operator creates a buffer 

(or buffers) with a size equal to the distance specified around the source feature (or features), then returns all 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

the features that are intersecting the

 buffer

 (or buffers)

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Completely contain 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

For a feature to be considered as completely containing another feature, each point in the geometry of  the source feature (reference) must fall inside the geometry of  the target (to be selected) feature, excluding its boundaries

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8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

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 Are completely  within

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

For a feature to be considered as being completely within another feature, each point in the geometry of  the target (to be selected) feature must fall within the geometry of  the source feature excluding its boundaries. This is the reverse operator from Completely contain

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 Are within

This method differs completely within method in that the geometry of  the target (to be selected) feature must fall inside the 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

geometry o  t e source feature even if  it touches it boundaries

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Have their  center  in A target feature will be 

selected by this operator geometry  falls into the geometry  of  the source 

 feature or  on its boundaries

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

You can also specify a distance

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Share a line segment  with

With this method, the source and target considered as sharing a line segment if  their geometries have at least two contiguous vertices in common

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

The source and target features must be either lines or polygons

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Touch the boundary  of 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location15

 Are identical  to

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

Two features are considered identical if  their geometries are strictly equal

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 Are crossed  by  the outline of 

The boundaries of  the source target (to be selected) features must have at least one edge, vertex, or endpoint in 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

common.

The source and target features must be either lines or polygons

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Contain

A polygon representing the United States will contain the State of  Texas even though its boundaries overlap along the 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

southern border of  the US

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Select  by  Location

Intersect 

Select all the villages in the West Bank that are within areas that at an elevation of  400 to 500 m

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location19

Select  by  Location

 Are within a distance of 

To select all the rainfall stations in Gaza Strip that are at a distance less than or equal to 200 meters 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

 regional road network

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8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

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Select  by  Location

 Are within a distance of 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location21

Select  by  Location

 Are within a distance of 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location22

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Select  by  Location

 Are Completely  Within

To select all the groundwater monitoring wells that are located within Gaza City

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location23

Select  by  Location

 Are Completely  Within

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location24

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Finding Features that  Intersect  Other  Features

Find the municipalities that are at high risk of  groundwater contamination

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location25

Finding Features that  Intersect  Other  Features

Highlight the risky areas

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location26

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Finding Features that  Intersect  Other  Features

Select the governorates that intersects with the selected features in the vulnerability theme

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location27

Select  by  Location

For example, there is containment (where the contained feature may touch the boundary of  the containing feature and com lete containment where the boundaries may not touch)

To select features by location

You choose two layers and specify a spatial 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location28

re at ons p

Features in the first layer are then spatially comparedto features in the second layer and the features will be selected if  they satisfy the relationship

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Selection of  Methods

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location31

Selection Based  on Intersecting

the Points

Base: points, lines, or polygons

Cyan features are selected in base

Comparison: points

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location32

 Red features represent comparison geometry

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Selection Based  on Intersecting

the Lines

Base: points, lines, or polygons

Comparison: lines

Cyan features are selected in base

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location33

 Red features represent comparison geometry

Selection Based  on Intersecting

the Polygons

Base: points, lines, or polygons

Comparison: polygons

Cyan features are selected in base

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location34

 Red features represent comparison geometry

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Within a Certain Distance of 

the Points

Cyan features are selected in base

geometry 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location35

Red features represent comparison geometry

Pick  a Method 

Find potential areas for a landfill site (polygons) that are 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location36

8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

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Pick  a Method 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location37

Pick  a Method 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location38

8/4/2019 [6-1] Analyzing Spatial Relationships - Selection by Location

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Pick  a Method 

You would like to organize a tour to weather stations in 

Yet you want only to visit stations that are not far from your office (so that you will not drive too far) and close to the main road (so that you will not walk)

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location39

Pick  a Method 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location40

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Pick  a Method 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location41

 A Good  Example to Work  On

You will be selecting a potential location for constructing a groundwater pumping well in a specific governorate

A set of  concurrent conditions should be fulfilled for determining the potential locations

A potential location should be at a distance of  at least 3 

[6- 1] Fall – 2 010 – G IS Dr. Mohammad N. Alm asri Sel ect ion by Location

 , 

2 km at most from main roads, located in high recharge areas (>150 mm/year), and is not in agricultural areas

The governorate is Jenin Governorate

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