The systematic division into section sheets adopted in the International World Map is the standard in many countries. This division is used for most types of small-scale maps. Due to the scope of application, it is also often the basis for indexing orthophoto images and data from laser scanning. Data accummulated in central State resources cover entire countries. Their coverage includes more than information obtained and processed for the users’ needs in the source format. Increasingly often, data is transformed into formats that facilitate their application (e.g. setting up a GRID for a digital terrain model). The need for quick spatial identification is a determinant of the availability of resources stored in these databases. The dynamic development of Open Source software in the fields of GIS is another increasingly broad area of study, and the research focus of scientists from around the world. They see it not only as a ready-made tool for conducting spatial analyses, but also in terms of searching for algorithmic solutions to meet the needs resulting from the requirement to process ever larger amounts of this type of data. The present paper discusses the method for designating a map sheet identification number (index) in a selected scale, based on the longitude and latitude of the given point. An unquestionable advantage of the presented solution is the possibility of dividing map sheets into scales, which were missing in their basic description. It follows from the fact that this spatial indexing method is indispensable for large amounts of data.