Design your database Much to the amazement of many, a good database is one which has been thought through and designed , rather than merely thrown together. The database design stage is of vital importance in any project involving GIS or other graphical applications which rely upon large volumes of data. In many ways, the database design itself is as important as the data. After all, the best dataset in the world is useless if you have entered it into a database design which is incapable of managing sensible queries of the data. The pages of the database service here at Newcastle provide pointers to more detailed database information.
Errors are everywhere .
There are probably some in this document, and there are bound to be plenty in any large database. In spatial terms, an error is the difference between the actual location or database entry and that which is stored. It is impossible to eliminate error, and the best that is usually possible is to be aware of likely errors and to allow for them in any display or analysis. Identify the acceptable tolerances for any task, and decide whether the likely error introduced while undertaking the task renders the task worthless with regard to these tolerance criteria A common mistake in GIS applications which introduces massive errors is the combining of data collected at very different scales. Whenever data of differing resolution are combined, the new whole should always be analysed at the resolution of the coarsest constituent data set.