Question 1

Euclidean distance between two points is:

Accepted Answer

The straight-line distance across a plane. Euclidean distance is the as-the-crow-flies planar distance. Network distance follows links, Manhattan distance sums axis offsets, and great-circle distance follows the curved surface of the sphere.

Question 2

Compared with a 1:250,000 map, a 1:10,000 map is:

Accepted Answer

Larger scale, covering less ground in more detail. Scale is the representative fraction, and 1/10,000 is a larger number than 1/250,000. Large-scale maps show small areas in great detail; small-scale maps show large areas with heavy generalisation.

Question 3

A survey crew records 30 GPS fixes at a benchmark. The fixes fall within 0.3 m of each other but their centre lies 12 m from the benchmark's published position. The readings are best described as:

Accepted Answer

Precise but not accurate. Precision describes repeatability (the tight 0.3 m cluster); accuracy describes closeness to the true value (missed by 12 m). High precision with a large systematic bias is precise but inaccurate.

Question 4

A land-suitability study overlays five polygon layers digitised from different sources, each with its own positional error. What should the analyst expect in the result?

Accepted Answer

Uncertainty propagates and compounds, producing sliver polygons and composite error greater than any single input. Each overlay combines the positional uncertainty of its inputs, so boundaries that should coincide produce slivers and the output is no more reliable than its worst input, and usually less. Error propagation is a core reason to document lineage and accuracy.

Question 5

An accuracy assessment of a parcel layer yields a horizontal RMSE of 2.0 m against independent survey checkpoints. Under the common 95 percent confidence reporting convention for horizontal accuracy (multiplying radial RMSE by about 1.73), the reported accuracy is approximately:

Accepted Answer

3.5 m. Accuracy at the 95 percent level is reported as roughly 1.7308 times the radial RMSE, so 2.0 m RMSE corresponds to about 3.5 m. The RMSE itself is a typical error, not the bound that 95 percent of points fall within.

Conceptual Foundations: GISP practice questions

Euclidean distance between two points is:

Compared with a 1:250,000 map, a 1:10,000 map is:

A survey crew records 30 GPS fixes at a benchmark. The fixes fall within 0.3 m of each other but their centre lies 12 m from the benchmark's published position. The readings are best described as:

A land-suitability study overlays five polygon layers digitised from different sources, each with its own positional error. What should the analyst expect in the result?

An accuracy assessment of a parcel layer yields a horizontal RMSE of 2.0 m against independent survey checkpoints. Under the common 95 percent confidence reporting convention for horizontal accuracy (multiplying radial RMSE by about 1.73), the reported accuracy is approximately:

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