Vector data represents geographic features as points, lines and polygons, while raster data represents them on a grid. The components of a GIS are hardware, software, data, people and methods. Spatial data describes the location of geographic features, while attribute data describes their characteristics. Georeferencing adds geographic coordinates to images so GIS software can place them in the correct real-world position. Topology expresses spatial relationships between vector features, while non-topology does not. Data quality includes completeness, considering holes, unclassified areas and compilation procedures that may have eliminated data.

1. St.Xavier’s Catholic College of Engineering
Chunkankadai, Nagercoil – 629 003
Two Mark questions with Answer
Degree: B.E./B.Tech. Department: CE Year/Semester : V
GI 8014 – GEOGRAPHIC INFORMATION SYSTEM
1 What is vector and raster data?
Vector Data- point, line, polygon
Raster data- girid forma
2 List the various components of GIS.
1. Hardware
2. Software
3. Data
4. People
5. Method
3 Differentiate between spatial and non-spatial data.
1. Spatial data
Describes the absolute and relative location of geographic features.
2. Attribute data or Non-spatial data
Describes characteristics of the spatial features. These characteristics can be quantitative
and/or qualitative in nature.
4 What is data compression?
 Data compression refers to the reduction of data volume.
5 What is georeferencing?
 Process of taking a digital image
 It could be an aerial photo, a scanned geologic map, or a picture of an topographic map.
 Adding geographic information to the image so that GIS or mapping software can ‘place’ the
image in appropriate real world coordinate position.
6 Differentiate between topology and non-topology.
 Topology expresses explicitly the spatial relationships between connecting or adjacent vector
features (points, polylines and polygons) in a GIS.
 Non Topology expresses explicitly not spatialyl relationships between connecting or adjacent
vector features (points, polylines and polygons) in a GIS.
7 State the completeness in data quality.
The final quality component involves a statement about the completeness of the data set. This
includes consideration of holes in the data, unclassified areas, and any compilation procedures that
may have caused data to be eliminated.
8 Describe OGC in data quality.
Global forum for collaboration of developers and users of spatial data products and services
Advance development of international standards for geospatial interoperability.
9 What is distributed GIS?
It is distributed for all fields
10 Differentiate the Enterprise and Desktop GIS.
Enterprise GIS for company use and Desktop GIS for individual use
11
List out the data input methods.
• Grid overlay
• keyboard
• Digitizer
• Scanner

2. 12 Define map projection.
Mathematical transformations of the 3-D model of the surface of the earth onto a 2-D map.
13 List out the raster data file formats. BMP (Bitmap Image)
• TIFF (Tag Index File Format)- a format for storing raster graphics images
• JPEG/JPG (Joint Photographic Expert Group)
• IMG (Image File Format)
• GIF (Graphic Intercharge Format)
• PSP (Portable Sony Play station)
• CDR (Crash Data Retrieval)
14 What is meta data?
defined as ‘data about data’, metadata helps to make data findable and understandable
15 Describe interoperability?
the ability of two or more systems or components to exchange information and to use the
information that has been exchanged”
16. List few standard GIS software.
Vector-
Raster-
Univ.)
17. What are the different types of raster GIS models?
1. Cell-by-Cell Encoding
2. Run Length Encoding
3. . Quad Tree
18. Define GIS.
A computerized system designed to capture, store, manipulate, analyse, manage and present all types
of geographically referenced data.
19. What is a data model?
 Data model is the objects in a spatial database plus the relationships among them.
 Coordinates are used to define the spatial location and extent of geographic objects.
Attribute/non-spatial data are linked with coordinate data to define each spatial object in the spatial
database