GIS

Question 1

What is GIS?

Answer 1

Is a collection of computer hardware and software components,spatial data ,people ,policies and procedures that have functional ability to facilitate to capture,manage , analyse and visualisation of spatially referenced data and support-making processes related to geographic space and location

Question 2

Components of GIS

Answer 2

Hardware
Software
Data
People
Policies and procedures

Question 3

What is metadata and why is it important?

Answer 3

Is data about data.

It allows the user to making an informed decision as to whether the data is suitable for their application purpose or not.

Question 4

Topology and list examples of the three main topological relationships

Answer 4

Topology- is a branch of mathematics that describes how spatial objects are related to each other

Relationships
Connectivity.specifying which chains are connected at which nodes
Direction. Defining a from node to a to node of a chain
Adjacency.indicating which polygons are adjacent on the left and which were adjacent on the right side of a chain

Question 5

What are major data models used in GIS? Explain the differences

Answer 5

Vector data model- data computation is complex
Data structure is complex

Raster data model- easy to perform calculations on raster layers
Sinple data structure

Question 6

TINS stands for what?
Give strengths and weaknesses

Answer 6

Triangulated irregular network

Strengths
- accurately reflects data sample as surveyed
-more efficient data storage than DEM
- Contours calculated directly from field observations.

Weaknesses
Uneven distribution of points not suitable for many types of spatial analysis
-contours generated from tin are often have spiky appearance ,thus manual enhancement is required

Question 7

Contour line

Answer 7

A line that joints the points of equal elevation

Question 8

Uses of DEMS and DTMs

Answer 8

Determining attributes of terrain,such as elevation at any point.
Finding features such as drainage basins and watershed

Question 9

GPS-Global Positioning System

Answer 9

Is a satellite based navigation system used extremely for marine and air navigation and for precise navigation

Question 10

Any two GPS errors

Answer 10

Natural error
Instrumental error

Question 11

Purpose of setting-out?

Answer 11

Correct plan position
Correct level
Correct size