Final answer:
Phone-based GPS systems can have spatial errors due to relativistic effects that require adjustments for timing and location accuracy, as well as signal obstruction from environmental factors like buildings and atmospheric conditions.
Step-by-step explanation:
Phone-based GPS systems are a marvel of modern technology, but they do have limitations that can lead to spatial errors. When considering the reliability of GPS readings, we must take into account factors like precision and accuracy. Precision refers to how close the GPS measurements are to each other, and accuracy is about how close those measurements are to the true location. One of the issues affecting both precision and accuracy is the need to account for relativistic effects. Because GPS satellites travel at high speeds and are positioned in weaker gravitational fields than we experience on Earth, both special and general relativity must be considered to maintain the system's accuracy. Without adjustments for these effects, the timing and thereby the location accuracy provided by GPS would deteriorate rapidly.
Moreover, localized factors such as signal obstruction can cause spatial errors. Tall buildings, dense foliage, and even atmospheric conditions can disrupt the GPS signals, leading to decreased precision and accuracy. In the real-world scenario of attempting to locate a restaurant with a GPS, these errors could manifest as readings that suggest the restaurant is located farther away (low accuracy) or spread the location points widely (low precision).