What is a GIS system?
A: First, GIS is a System. It draws on many sources for input, and affects many different parts of society. The system can support natural resource officials, planning departments, transportation, waste disposal, government officials, law enforcement, and private residents to name a few.
Digital Information, housed in a computer database, makes the system work. That's called Data. In Sussex County, some data is obtained from the State of New Jersey, other data is obtained through county departments or non-profit agencies and some old fashioned personal investigation fills in any missing pieces.
Finally, the bits of information all take the shape of lines, text, points, or fields that relate to specific Geographic locations on the earth.
The System is based on Information, and the Information is Geographically located. That obviously means mapping the landscape is part of GIS, but it is not the whole picture by any means. You can see municipal boundaries, land use, wetlands and property lines (among many other things) with GIS, most of which you can see in our map library.
What does a GIS do for me?
A: That all depends on who I am. If I'm a private citizen, it lets me understand my community better. It tells me where the high crime zones are. It tells me where my kids go to school, and what my voting district is. If I'm a merchant, it tells me where the most population density is, and what the traffic patterns are. It tells me where I should set up a new shop, and where to advertise. If I'm a city planner, it tells me where to build and how to re-route traffic if necessary. If I'm a conservationist, it tells me whether protected wildlife areas are too close to major sources of pollution. Whoever I am, GIS helps me make informed decisions by showing a picture of the real world I can understand.
How do I get to your office?
Click the following link for directions to our office: Directions
How do I use the online viewer?
Click the following link for instructions about using our online viewer: Viewer Instructions
How do I access the online viewer?
Click the following link to access our online viewer: Online Viewer
What are Geographic References?
Geographic information contains either an explicit geographic reference, such as the New Jersey state plane coordinate or latitude and longitude, or an implicit reference such as an address, postal code, census tract name, or road name. An automated process called geocoding is used to create explicit geographic references (multiple locations) from implicit references (descriptions such as addresses). These geographic references allow you to locate features, such as a business and events, such as a hurricane, on the earth's surface for analysis.
What are Vector and Raster Models?
Geographic information systems work with two fundamentally different types of geographic models--the vector model and the raster model. In the vector model, information about points, lines and polygons are encoded and stored as a collection of x,y coordinates. The location of a point feature, such as an inlet, can be described by a single x,y coordinate. Linear features, such as roads and rivers, can be stored as a collection of point coordinates. Polygonal features, such as watershed areas and zoning, can be stored as a closed loop of coordinates. The vector model is extremely useful for describing discrete features, but less useful for describing continuously varying features such as elevation or precipitation.
The raster model has evolved to model such continuous features. A raster image comprises a collection of grid cells similar to a scanned map or picture. Both the vector and raster models for storing geographic data have unique advantages and disadvantages.
Modern GIS's are able to handle both models.