GIS For Dummies

ESRI and its software users have created an ever-increasing array of industry-specific schemas that they refer to as geodatabase models. ESRI intended not only to share these schemas, but also to use them as examples for other industries when developing their own schemas.

Raster data give you more options to work with surfaces than vector data.

Raster data takes up more computer space than vector data.

When you treat networks as corridors, the movement of fluids, objects, animals, and/or vehicles is your primary concern. For any movement, the nature of the network as a corridor has an impact on how fast things move and in some cases, even whether they move at all. The resistance to movement is called impedance and can be a function of the size of

Raster is more powerful for modeling than vector.

When you establish a relational join, all the information in the first table is shared with all the information in the second table, which is much easier than trying to make a huge, complex, comprehensive table from scratch. It's much easier to design small, individual, focused tables (that can be related to other small ones) than to create large,

No matter what type of geographic setting or scales of geographic data you use in GIS, you need to link the graphics with meaningful descriptive data. When you perform geographic analysis, you search, manipulate, compare, and analyze this data. Every GIS software package must manage descriptive data and link them to their respective objects on the

The geodatabase (not to be confused with a collection of geocoded data inside a GIS software package that's sometimes referred to as a geodatabase) allows you to store a wide variety of data types (including raster, vector, CAD, and others) in the same system.

One other factor both characterizes the complexity of a network and adds to the robustness of traffic modeling capabilities. That characteristic, called circuitry, is based on the idea of closed loops. Closed loops allow moving objects, fluids, and so forth to travel alternate routes when moving along a network