THEORY EXAMINATION (SEM–VI) 2016-17 GEOGRAPHIC INFORMATION SYSTEM

GEOGRAPHIC INFORMATION SYSTEM (NIT065)

SECTION – A

(Short Answer Questions | 2 Marks Each)

(a) Different Types of Maps

Maps are classified as physical maps (show natural features like rivers and mountains), political maps (show boundaries and cities), thematic maps (show specific themes like rainfall or population), and topographic maps (show elevation and contours).

(b) Attribute Data vs Spatial Data

Spatial data represents location and geometry (point, line, polygon), such as location of roads.
Attribute data describes characteristics of spatial features, such as road name or width.

(c) GIS as a Decision Support System

GIS acts as a decision support system by integrating spatial and non-spatial data, analyzing alternatives, and supporting planning and management decisions.

(d) Euler Equation

Euler equation states that for planar graph:
V − E + F = 1
where V = vertices, E = edges, F = faces.

(e) Trends in GIS Technology

Major trends include web-based GIS, mobile GIS, cloud GIS, real-time GIS, and integration with AI and remote sensing.

(f) Use of Nominal and Ordinal Measurement

Nominal data classifies data into categories (land use type).
Ordinal data shows order or ranking (soil quality: high, medium, low).

(g) Map Projection

Map projection is the method of transforming the earth’s curved surface onto a flat map.

(h) Tessellation

Tessellation is the division of geographic space into non-overlapping cells, commonly used in raster GIS.

(i) Scanner Characteristics for Raster Maps

Typical scanners have high resolution, color depth, accuracy, and scanning speed for digitizing maps.

(j) Need of Normalization and ODBC

Normalization reduces data redundancy and improves database integrity.
ODBC (Open Database Connectivity) allows GIS to connect with different databases.

SECTION – B

(Descriptive Questions | 10 Marks Each)

(a) Map Projections: Types, Advantages & Limitations

Map projections are classified into cylindrical, conical, and azimuthal projections. Cylindrical projections are useful for world maps but distort polar regions. Conical projections are suitable for mid-latitude regions. Azimuthal projections preserve direction but distort area and shape.

(b) Sources of DEM in GIS

DEM sources include satellite imagery, LiDAR, photogrammetry, and ground surveys. Satellite DEMs cover large areas but have moderate accuracy, while LiDAR provides high accuracy but is costly.

(c) Gridded DEM vs TIN DEM

Gridded DEM uses regular square cells and is simple but less accurate for complex terrain.
TIN DEM uses irregular triangles, provides better terrain representation, but is computationally complex.

(d) GPS Integration with GIS

GPS provides accurate real-time location data which improves mapping accuracy, field data collection, and updating of GIS databases.

(e) GIS and Its Components

GIS is a system for capturing, storing, analyzing, and displaying spatial data. Components include hardware, software, data, people, and methods.

(f) Geometry of Regular Tessellations

Regular tessellations consist of uniform shapes like squares or hexagons that cover space without gaps or overlaps.

(g) Vector vs Raster Data Models

Vector data uses points, lines, and polygons and is precise for boundaries. Raster data uses grid cells and is suitable for continuous data like elevation.

(h) Errors in Digitization

Errors include overshoots, undershoots, slivers, distortion, and attribute errors, which affect data accuracy.

SECTION – C

(Long Answer Questions | 15 Marks Each)

3) Raster File Formats in GIS

Common raster formats include TIFF, GeoTIFF, JPEG, IMG, GRID, and PNG. GeoTIFF supports georeferencing, JPEG offers compression but loses quality, while IMG and GRID are widely used for DEM and satellite data.

4) Functions of DBMS and Database Structures

DBMS manages data storage, retrieval, security, and integrity.
Database structures include hierarchical, network, relational, and object-oriented. Relational databases are most common due to flexibility and ease of query.

5) Levels of Measurement & Digital Cartography vs GIS

Levels of Measurement:
Nominal (categories), Ordinal (ranking), Interval (difference meaningful), Ratio (true zero).

Digital Cartography vs GIS:
Digital cartography focuses on map creation and visualization, while GIS supports spatial analysis, modeling, and decision-making.