Lecture 3-Vector Data Processing and Coordinate System

Vector data processing and

Coordinate System

1

Vector Data Processing

2 Sarfaraz Alam, [email protected]

Union

Computes a geometric

union of the input

features.

All features and their

attributes will be written to

the output feature class.

3 Sarfaraz Alam, [email protected]

Erase

Creates a feature class by

overlaying the Input

Features with the polygons of

the Erase Features.

Only those portions of the

input features falling outside

the erase features outside

boundaries are copied to the

output feature class.

4 Sarfaraz Alam, [email protected]

Dissolve

Aggregates features based on

specified attributes.

5 Sarfaraz Alam, [email protected]

Intersection

Computes a geometric

intersection of the input

features.

Features or portions of

features which overlap in

all layers and/or feature

classes will be written to

the output feature class.

6 Sarfaraz Alam, [email protected]

Split

Splitting the Input Features

creates a subset of multiple

output feature classes.

The Split Field's unique values

form the names of the output

feature classes. These are

saved in the target workspace

7 Sarfaraz Alam, [email protected]

Clip

Extracts input features that overlay

the clip features.

Use this tool to cut out a piece of

one feature class using one or more

of the features in another feature

class as a cookie cutter.

8 Sarfaraz Alam, [email protected]

Buffer

Creates buffer polygons around input

features to a specified distance

Analysis Tools Proximity Buffer

9 Sarfaraz Alam, [email protected]

Buffer

Fixed Distance Buffer

10 Sarfaraz Alam, [email protected]

Variable Distance Buffer

Buffer

11 Sarfaraz Alam, [email protected]

Fixed Distance Buffer

Buffer

12 Sarfaraz Alam, [email protected]

Variable Distance Buffer

Near

Determines the distance from each

feature in the input features to the

nearest feature in the near features,

within the search radius.

13 Sarfaraz Alam, [email protected]

Generalization

14 Sarfaraz Alam, [email protected]

Coordinate system

15

Fig: Shape of

the Earth

Spherical Coordinate

+ =

Spherical Coordinate

Map Projection

• A map projection is a systematic transformation of the latitudes

and longitudes of locations on the surface of a sphere or

an ellipsoid into locations on a plane.

• Map projections are necessary for creating maps. All map

projections distort the surface in some fashion.

• Depending on the purpose of the map, some distortions are

acceptable and others are not; therefore different map projections

exist in order to preserve some properties of the sphere-like body

at the expense of other properties.

• There is no limit to the number of possible map projections.

Types of Map Projection

Map projections are classified in several ways

• Based on geometrical model of projection

• Based on orientation

• Based on pattern of deformation

Fig: Transformation From 3 dimension to 2

dimension

Classification based on geometrical model of projection

•Azimuthal Projection

•Cylindrical Projection

•Conical Projection

Universal Transverse Mercator projection

Zones are each six degrees of longitude, numbered as

shown at the top, from W to E

Define coordinate in ArcMap

Geographic

Coordinate

System

World

WGS1984

Coordinate Transformation in ArcMap

Coordinate system can

be transformed from one

to another using Project

tool

Class Work

25

Thank you

26