Introduction of Vector Data

Introduction

There are three changed means to think about vectors. A vector as;

  • An array of numbers (a computer science vision)
  • An arrow with a direction and magnitude (a physics outlook)
  • An object that follows addition and scaling (a mathematical view)

In this article, we will understand about Vector Data in detail.

Description

  • Vector data provides particular features on the Earth’s outward.
  • It allocate attributes to those features.
  • Vectors are composed of separate geometric locations (x, y values).
  • These are recognized as vertices that describe the shape of the spatial object.
  • The group of the vertices describes the type of vector.
  • That we are working with as point line or polygon.

Introduction of Vector Data

Points

  • Each point is well-defined by a particular x, y coordinate.
  • There may be several points in a vector point file.

Examples

  • Sampling locations
  • The site of individual trees
  • The position of survey plots.

Lines

  • Lines are composed of various points that are related. At least two points are needed.
  • For example, a road and a stream can be denoted by a line.
  • This line is composed of a sequences of segments.
  • Each curve in the road and a stream signifies a vertex that has defined x, y location.

Polygons

  • A polygon contains of three or more vertices that are linked and wrapped.

Examples

  • The shapes of survey plot boundaries
  • Outline of lakes
  • Sketch of oceans
  • States or countries

Vector data in GIS environment

  • Maximum GIS applications collection vector features into layers.
  • Features in a layer have the similar geometry type such that they would all be points.
  • They have the equal types of attributes such that information about what classes a tree is for a trees layer.
  • For instance if we have logged the positions of all the footpaths in our school, they would generally be kept on the computer hard disk.
  • Those will be shown in the GIS as a single layer.
  • This is suitable as it permits us to hide or show all of the features for that layer in our GIS application with a single mouse click.

Cutting out vector data

  • The GIS application will permit us to make and adapt the geometry data in a layer.
  • This process is named digitising.
  • The GIS application will merely permit us to make new polygons in that layer if a layer comprises polygons.
  • Likewise, the application would only permit us to do it if the altered shape is correct and if we want to change the figure of a feature.
  • For instance it won’t let us to edit a line in such a way that it has only one vertex.
  • As all lines must have at least two vertices.
  • Making and editing vector data is a vital function of a GIS.
  • Ever since it is one of the core means in which we can make personal data for things we are interested in.

Example

  • We are observing pollution in a river.
  • We could use the GIS to digitise all vents for storm water drains.
  • We could similarly digitise the river itself as a polyline feature.
  • Lastly we could take readings of pH levels beside the course of the river.
  • Digitise the spaces where we made these readings as a point layer.
  • There is many free vector data that we can obtain and use on top of making our own data.
  • We can get vector data for instance that seems on the 1:80 00 map sheets from the Chief Directorate: Surveys and Mapping.

Pros and Cons of Vector Data

Advantages

  • The geometry that one covers data about what the dataset maker said was vital.
  • The geometry structures grip facts in themselves.
  • For example why select point over polygon?
  • Each geometry feature may carry many attributes in place of just one.
  • For example, a database of cities may have qualities for name, country, and population.
  • Data storage can be very well-organized likened to rasters

Disadvantages

  • Possible loss of part likened to raster.
  • Potential prejudice in datasets. What didn’t become recorded?
  • Designs linking many vector layers essential to do math on the geometry along with the attributes, therefore can be slow related to raster math.