This paper presents a general parametric analysis of deterministic production-location and design-location problems. The analysis characterizes the effects of changes in output level, input and output prices, and transport rates on the firm's optimal production and location solutions. The approach, which uses arguments similar to those used in revealed preference analysis, does not rely on differential methods, so that it is applicable to more general situations, such as non-differentiable production and transport cost functions, and does not assume interior optimal locations. Several numerical examples are provided to explain major results and to illustrate apparent anomalies which can occur in spatial economic models.