As a GIS (Geographic Information System) specialist or construction project manager working with a GIS platform, it is essential to have a thorough understanding of the various GIS data types available. GIS data types are divided into two main categories: vector and raster data. Each data type has its unique geographical characteristics, as well as its own advantages and disadvantages, which make it suitable for specific real world applications.

Understanding Vector GIS Data

Vector data is a type of GIS data that represents attributes on the earth's surface as points, lines, and polygons. It is commonly used to map discrete features such as roads, buildings, and water bodies. Vector data is stored as a series of x, y coordinates that define the shape and location of each feature. The three main types of vector data are point, line, and polygon features.

Point features refer to individual locations such as a city, a hospital, or a specific GPS coordinate. There is zero dimension to this data type, so it is not used to manage length or area.

Line features represent linear features such as roads, rivers, and pipelines. Since line data has only one dimension, it is only used to measure length.

Lastly, polygon features represent areas such as land parcels, parks, and lakes. These geometry-based features are two dimensional and are often used to signify perimeters.

The advantages of vector data are its ability to represent complex shapes and the ability to overlay data sets. However, the disadvantage is that it is not suitable for analyzing continuous data, such as elevation or temperature.

Vector data can be obtained from various sources, including:

1. Government agencies: Many governments provide free access to vector data on their websites. For example, the US Census Bureau provides boundary files for states, counties, and cities.

2. Commercial vendors: Companies such as TomTom, HERE, and TeleAtlas provide vector data for a fee. These data sets are commonly used in navigation and mapping applications.

3. Open data portals: Many cities and states provide open data portals where vector data can be downloaded for free. For example, the city of San Francisco provides various GIS data layers, such as land use, zoning, and street centerlines.