Final answer:
A low HDOP number such as 2 indicates a high level of precision in GPS measurements, meaning the satellite geometry provides a favorable condition for a precise position measurement.
Step-by-step explanation:
A low HDOP (Horizontal Dilution of Precision) number such as 2 indicates a high level of precision. HDOP is a measure of the geometric strength of satellite configuration during a GPS fix, and a low HDOP value signifies that the position measurement is more precise because the satellite geometry is more favorable. This does not necessarily mean the accuracy is high, as accuracy refers to how close the GPS measurements are to the true location, which can be affected by other kinds of errors.
To understand the difference, consider a dartboard analogy: High precision is similar to throwing darts that land close to each other (Figure 1.22), while high accuracy is like hitting close to the bull's-eye. You can have high precision with low accuracy if the darts are close together but far from the bull's-eye, indicating a consistent but incorrect measurement.Accuracy refers to how close a measured value is to the true or target value, while precision refers to how close multiple measurements are to each other.Therefore, a low HDOP number indicates that the measurements are relatively close to the true value, indicating high accuracy, but they may be spread out from each other, indicating low precision.