What is the meaning of resolution applied to GIS data and raster images and what resolution do I need?
All GIS systems allow you to keep enlarging and zooming in on a smaller area. Both vector data and image data eventually degrade, the vector data becoming a series of straight lines and the raster data a collection of individual pixels. For both types of data, detailed work needs as high resolution data as possible. Some of our images are really high resolution. You can enlarge the image much more than on the original paper without it breaking up. But they may be large (20MB or more). vector data is more economical in its use of storage space. It is not always a good thing to have high resolution data. High resolution is not good for maps of a large area such as the whole of South Asia. For example, using high resolution data to display the coastline of Bangladesh results in a blurred and messy line. If you display the drainage data for Bangladesh which comes with the Digital Chart of the World and colour the drainage channels blue, the whole country turns blue unless you zoom in on a
