GATE GE Part B1 or B2? Choosing Surveying vs Image Processing

Every GATE Geomatics candidate answers the compulsory Part A (55 marks) and then one of two 30-mark parts. Part B1, Surveying and Mapping, covers maps, land surveying and aerial photogrammetry. Part B2, Image Processing and Analysis, covers quantization, image processing, corrections, enhancement, transformation and classification. The choice worries candidates more than it should, for two reasons from the brochure. You make it in the exam hall, not at registration. And there is no separate B1 or B2 score or rank: everyone gets one score. This guide sets out what four years of papers say about each part and ends with a chooser.

GATE 2027 Information Brochure (GE structure; section-wise scores not provided for GE); topic counts from the GE 2027 syllabus.

Because there is no separate rank, the only thing that matters is which part gets you more marks. There is no “prestige” part and no programme that prefers one. Since you choose in the hall, the practical plan is to prepare one part properly and know the other well enough to recognise an easy paper.

The data points one way for a candidate who wants predictability. B1 is the steadier part: three topics, each within two questions of its average, with numericals (NAT) that reward practice and no fear of partial credit. B2 is broader and swings more, and in 2026 more than half its marks were MSQs, where you must pick exactly the right set of options. On the other hand, B2 overlaps Part A: resampling, contrast and covariance questions appear in Part A too. So B2 preparation also earns Part A marks, which B1 preparation does less often.

What GATE does not publish: how many candidates chose each part, or how they scored. So no one can tell you that one part is “scoring”. Anyone who claims so is guessing.

The revision moves both parts, in opposite directions. B2 loses the Fourier transform, which sat inside its largest topic (data quantization and processing, about 6.75 marks a year) and was asked in every paper from 2024 to 2026. It gains supervised and unsupervised classification with accuracy analysis, which the setters had already been asking. The net effect for a B2 candidate (our reading) is a part that is a little less mathematical and a little more about interpreting images and error matrices. B1 gains COGO functions on the total station and loses two photogrammetry words, so a B1 candidate’s preparation is almost unchanged: the traverse and coordinate computations that COGO performs were already the core of land surveying.

The marking rules are the same for both parts, and they matter more than the topic list. An MCQ answered wrongly costs one-third of its marks (one-mark questions) or two-thirds (two-mark questions). MSQ and NAT questions carry no negative marks, but an MSQ earns nothing unless you choose exactly the right set of options: there is no partial credit. A part heavy in MSQs, as B2 was in 2026, therefore punishes a half-known topic in a different way from an MCQ-heavy part.

Our recommendation, not an official rule. Do Part A first; it is compulsory and worth 55 marks. Then spend five minutes reading the first few one-mark questions of both B parts and count how many you can answer at sight. If your prepared part is at least as good, stay with it. Switch only if the other part is clearly easier for you. Once you have chosen, do not answer questions in the other part: the brochure scores one B part, and time spent on the other is time lost.