Data Capture & Storage

There are two major methods of representing

spatial data, raster and vector. In the vector

model the spatial element of the data is represented

by a series of coordinates, whereas in the

raster model space is divided into regular pixels,

usually square. Each model has advantages and

disadvantages summarized but the

key factors in deciding on a format are resolution

and amount of storage required. A simple geological map in vector and

raster format. The raster method is commonly

used for remote sensing and discussed, whereas the vector method is used

for drillholes and geological mapping. Most

modern systems allow for integration of the

two different types as well as conversion from

one model to another, although raster to vector

conversion is much more difficult than that

from vector to raster.

In a simple (two-dimensional) vector model,

points are represented by

lines as a series of connected points (known as

vertices), and polygons as a series of connected

lines or strings. This simple model for polygons

is known as a spaghetti model and is that

adopted by computer aided drawing (CAD)

packages. For more complex querying and

modeling of polygons, the relationship between

adjoining polygons must be established and

the entire space of the study area subdivided.

This is known as the topological model. In this

model, polygons are formed by the use of

software as a mesh of lines, often known as

arcs, that meet at nodes. Another variation of

this model often used for height data is that of

the triangular irregular networks (TIN) and is

used to visualize digital elevation surfaces or

construct digital terrain models (DTM). The

TIN model is similar to the polygons used in

ore resource and reserve calculationx and y coordinates,