If too many attributes are put in each table, that map layer will be too crowded. The importance of database design comes through clearly in the experience of some land-related organizations, which have put their real energy into designing databases, prior to or while acquiring GIS software or data. The system is used to track species and ecosystems by members of the Natural Heritage Network, a collection of individual organizations that operate data centers, most within government agencies, across the western hemisphere. The Massachusetts Historical Commission's information assets are also concentrated in its database of historic properties and projects, developed and improved over many years. Only recently did MHC begin using a GIS to map the results of queries put to this database.
Relevant data is often available at little or no cost from a range of sources.
For some purposes, small-scale data may well be appropriate. Data on this scale can reveal how well the distribution of regional facilities matches the distribution of the people who use those facilities, or how well the distribution of conservation land matches the distribution of broad classes of ecosystem or habitat. Most GIS projects, however, involve adding some original data, produced by direct observation and surveys, to data purchased or acquired from other sources. In contrast, more detailed data can easily be aggregated to reveal broad landscape patterns, as well as answer questions about an individual site. However, detailed plotting is time consuming.