Recently in modern geoinformatics, the task of transforming coordinate systems has been one of the most significant. In this case, coordinate processing is performed for various projections, supported by many geographic information systems and the corresponding software libraries. At the same time, problems associated with transformation into specialized coordinate systems for example geomagnetic ones remain practically unsolved. Moreover, such a conversion is necessary to describe various geophysical processes, the occurrence and course of which largely depend on the parameters of the main magnetic poles of the Earth. In the paper, the authors proposed a web-based approach to transforming a geographic coordinate system into a geomagnetic one and ensuring prompt results based on the original spatiotemporal parameters. The architecture of the web solution was modernized by combining various web patterns; it provides support for a plug-in structure and loose coupling of program modules. It is shown that the proposed solution does not depend on the type of the consumer and can be used with interfaces of various kinds, provided that the appropriate interaction protocol is used. The performed computational experiments showed that calculations of geomagnetic coordinates based on the mentioned algorithm match to the known expressions and models