List of top Geographic Information System Questions asked in GATE Geomatics Engineering

Figure below shows the scatterplot of training pixels of water (w), sand (s), forest (f) and commercial (c) in bands 1 and 2. Pixel ‘A’ having digital number 4 and 6 in band 1 and band 2, respectively, is to be classified using k-nearest neighbor classifier having the value of k equal to 5. The assigned class for the pixel ‘A’ is ____________

The figure below shows a one-dimensional function, \( f \), and a filter \( w \). Consider \( f \) is padded with zeros on both sides. Which one among the following will be the final convolution output of \( f \) with \( w \) after the padding zeros are removed from the output?  \[ f = [0 \quad 0 \quad 1 \quad 0 \quad 0], \quad w = [1 \quad 2 \quad 3] \]

In supervised digital image classification, the number of combinations to be evaluated to select three best bands out of five bands is ____________ (Answer in integer).

Piecewise linear contrast stretch is performed on an 8-bit image. The output (\( BV_{{out}} \)) would be zero for input value \( BV_{{in}} \leq 80 \). The output (\( BV_{{out}} \)) would be 255 for \( BV_{{in}}>120 \). For the remaining input values, \( BV_{{out}} = (2 \times BV_{{in}}) - 20 \). If \( BV_{{in}} = 120 \), then \( BV_{{out}} \) is __________ (Answer in integer).

In levelling between two points P and Q on opposite banks of a river, the level was set up near P, and the staff readings on P and Q were 2.165 m and 3.810 m, respectively. The level was then moved and set up near Q and the respective staff readings on P and Q were 0.910 m and 2.355 m. The true difference of level between P and Q is __________ m (rounded off to 3 decimal places).

A level with the height of the instrument being 2.550 m has been placed at a station having a Reduced Level (RL) of 130.565 m. The instrument reads 3.665 m on a levelling staff held inverted at the bottom of a bridge deck. The RL of the bottom of the bridge deck is __________ m (rounded off to 3 decimal places).

A point is specified along the Greenwich Meridian at \(60^\circ\) N latitude on an ellipsoid. The parameters of the ellipsoid are semi-major axis \(a = 6378137\) m and flattening factor \(f = \frac{1}{298.224}\). The volume of the ellipsoid is given by \(\frac{4}{3} \pi a^2 b\), where \(b\) is the semi-minor axis. The latitude of the point on the sphere whose volume is the same as the volume of the ellipsoid of reference is __________N (rounded off to 2 decimal places).

In the figure below, \( I_1 \) and \( I_2 \) are the two instrument stations. The instrument stations and the object \( P \) lie in the same vertical plane. Assume all instruments and staff are levelled.

\( L \) = horizontal distance between the object and the station \( I_2 \)
\( b \) = horizontal distance between the instrument stations
\( S \) = staff reading at the Benchmark (BM) for horizontal line of sight
\( H \) = reading on the staff at \( P \)
\( r \) = height of the point sighted by instruments at the staff kept at \( P \) from the line of sight of the instruments
\( \alpha_1 \) and \( \alpha_2 \) = vertical angles to the reading on staff at \( P \) from \( I_1 \) and \( I_2 \), respectively

Which one of the following relationships is correct for \( L \)?

In a closed traverse PQRST the following data were collected in the field. What is the correct sum of deflection angles for this traverse?     

Figure below shows an open traverse PQRS, where P is the starting point of traverse and S is the end point of traverse. Which one of the following is correct? 

Two positions on the Earth’s surface are given in the form of Cartesian coordinates in the WGS84 reference frame and ellipsoid. The norm of difference of these two position vectors is the ____________

The scattering matrix for a fully polarimetric synthetic aperture radar pixel is given below. The \( C_{11} \) element of the covariance matrix computed with a \( 1 \times 1 \) window will be __________? (rounded off to 2 decimal places).

Here, \( i = \sqrt{-1} \).

\[ \begin{bmatrix} 0.1 + 0.5i & 0.1 - 0.1i \\ 0.1 + 0.1i & 0.3 - 0.5i \end{bmatrix} \]

In a given weighted graph shown below, what is the value of the expression \( (p + d)^2 \), where: 
[i.] Alphabets A, B, C, D, E, and F denote the nodes 
[ii.] Numbers 1 to 6 denote the weights between two nodes 
[iii.] \( d \) = shortest distance between node A and node E 
[iv.] \( p \) = number of paths with distance \( d \) 

The first value in the output of a SQL query (given below) when run on a table having name “Table-1” is?

SQL Query: SELECT LastName FROM Table-1 WHERE State = "IN" ORDER BY FirstName

The table below is an attribute table about employee records. Which attribute can be used as a primary key?