GIS Interview Question

Question 1 What is a coordinate system? 

 A coordinate system is a reference system used to represent the locations of geographic features, imagery, and observations such as GPS locations within a common geographic framework. 

 Each coordinate system is defined by:

 -> Its measurement framework, which is either geographic (in which spherical coordinates are measured from the earth's center) or planimetric (in which the earth's coordinates are projected onto a two-dimensional planar surface)

 -> Unit of measurement (typically feet or meters for projected coordinate systems or decimal degrees for latitude-longitude)

 -> The definition of the map projection for projected coordinate systems 

 -> Other measurement system properties such as a spheroid of reference; a datum; and projection parameters like one or more standard parallels, a central meridian, and possible shifts in the x- and y-directions 

 Question 2 Types of coordinate systems

 There are two common types of coordinate systems used in GIS:

 A global or spherical coordinate system such as latitude-longitude. These are often referred to as geographic coordinate systems. 

 A projected coordinate system based on a map projection such as transverse Mercator, Albers equal area, or Robinson, all of which (along with numerous other map projection models) provide various mechanisms to project maps of the earth's spherical surface onto a two-dimensional Cartesian coordinate plane. Projected coordinate systems are sometimes referred to as map projections.

Question 3 What is a spatial reference in ArcGIS? 

 A spatial reference in ArcGIS is a series of parameters that define the coordinate system and other spatial properties for each dataset in the geodatabase. It is typical that all datasets for the same area (and in the same geodatabase) use a common spatial reference definition. 

 An ArcGIS spatial reference includes settings for The coordinate system. 

The coordinate precision with which coordinates are stored (often referred to as the "coordinate resolution") 

Processing tolerances (such as the cluster tolerance) 

The spatial or map extent covered by the dataset (often referred to as the "spatial domain")

 Question 4 What Is The Difference Between Geo-coding And Geo-referencing? 

Answer : Geo-coding is when you associate a place name or an address with map coordinates. 

Geo-referencing is the process of associating plain digital images taken from a satellite or a plane with map coordinates so that they can be overlaid on street maps.

1. Question 5 Name The Two Data Structures That Have The Capacity To Hold Spatial Data.

   Answer :

   The two data structures that can hold spatial data include raster and vector.

   1. Question 6. Define Remote Sensing?

      Answer :

      Remote sensing refers to detection and classification of objects on or in earth without physical contact, generally attained through aerial sensors.

      
      

      1. Question 7 Differentiate Between Gis Commands And Tools?

         Answer :

         Commands do not require interaction with the map, they just rely on surface. Tools on the other hand require interaction with the map canvas.

         
         

         
         
         
         

      2. What is a Coordinate? 

         A coordinate is a set of values that show a position on earth. Coordinate systems use this information to tell us the distance between two or more points, location and direction. There are two types of coordinate systems : geographic and projected. 

         The Geographic Coordinate System combines coordinates and locations on a 3D spherical model of the earth. A datum is a factor, but not the only factor, in a geographic coordinate system. A datum represents everything you need to associate coordinates (typically lat/long/height – angular units) to a position on the Earth. For example, the datum “WGS84” means “use GPS to get a position”.

         The Projected Coordinate System, on the other hand, shows how a spherical earth model is projected onto a flat map. It uses cartesian coordinates (X,Y) which are measured in a particular unit, for example meters (m), feet (ft), etc. This is produced by an algorithm, otherwise known as a Projection.