ICAR AIEEA-PG — Forestry/Agroforestry & Silviculture (Major Subject Group 09) · India · National Testing Agency for ICAR
Original practice questions written to the published syllabus · not past papersReading the forest from above: aerial photographs and satellite images, spectral behaviour of vegetation, image classification, change detection and forest-cover monitoring.
In the exams: IFoS Forestry Paper II Section A (forest mensuration and remote sensing); ICAR AIEEA-PG Group 09 (aerial photo interpretation and remote sensing); ICAR AICE-JRF 59 Unit 4
How our questions for ICAR AIEEA-PG spread across the units of Remote Sensing & Photogrammetry for Forestry. Difficulty: 11 easy, 19 medium, 1 hard.
| Aerial photographs: scale, stereoscopy, parallax and tree height | 5 | |
| Satellite sensors and resolutions: spatial, spectral, temporal, radiometric | 4 | |
| Image classification: supervised and unsupervised; accuracy assessment | 4 | |
| Electromagnetic spectrum and spectral signatures of vegetation | 3 | |
| Forest cover and change detection | 3 | |
| Drones (UAVs) for forest survey | 3 | |
| Photo-interpretation keys for forest types | 2 | |
| Vegetation indices (NDVI and others) | 2 | |
| Radar (SAR) in forestry | 2 | |
| Fire detection and burned-area mapping | 2 | |
| National forest-cover monitoring systems | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
A camera with a 152 mm focal length is flown 3,040 m above flat ground. What is the photo scale?
D. 1:20,000
Scale = f ÷ (H − h) = 0.152 m ÷ 3,040 m = 1 ÷ 20,000, so 1:20,000. Forgetting to convert 152 mm to metres gives the wrong 1:20 or 1:200,000-type slips; 1:2,000 drops a zero.
Forward overlap (endlap) between successive vertical photos for stereo viewing is usually about:
D. 60%
About 60% forward overlap puts every point on at least two photos; side overlap is about 20–30%.
On a vertical photo flown 1,200 m above the base of a tree, the top lies 80 mm from the principal point and is displaced 2 mm. Using h = d × H ÷ r, how tall is the tree?
A. 30 m
Relief displacement: h = d × H ÷ r = 2 mm × 1,200 m ÷ 80 mm = 30 m. 133 m inverts d and r; 15 m halves H by mistake.
How many brightness levels can an 11-bit sensor record?
D. 2,048
2¹¹ = 2,048 levels. 22 multiplies 2 × 11 instead of raising 2 to the 11th power; 1,024 is 10-bit and 4,096 is 12-bit.
A forest pixel has NIR reflectance 0.45 and red reflectance 0.05. Using NDVI = (NIR − red) ÷ (NIR + red), NDVI is:
A. 0.80
NDVI = 0.40 ÷ 0.50 = 0.80. 9.00 is the simple ratio NIR ÷ red.
Image differencing for change detection involves:
B. Subtracting values between dates
Image differencing subtracts pixel values (or an index such as NDVI) of one date from another; a threshold on the difference then separates change from no change. Classifying a single image cannot show change on its own.
The grainy noise in SAR images is called:
A. Speckle
It comes from interference among many scatterers in a pixel and is reduced by multi-looking or filtering.
VIIRS active-fire detections have a resolution of about:
A. 375 m
VIIRS active-fire products are at 375 m, finer than MODIS active fires at 1 km. 30 m and 10 m are Landsat and Sentinel-2 class resolutions, used for burned-area mapping rather than daily active-fire detection.
Ten here, 31 in the app. The Laisha app has every practice question we have written to ICAR AIEEA-PG in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
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