Contents

• What is Raster Based GIS?
• Why Use A Raster GIS?
• Who Uses Raster GIS?
• What Are Raster GIS Applications?
• Advanced Analysis and Data Visualization
• Map Composition and Layout Facilities
• File Translators and Data Integration

Introduction to Raster Based GIS

There are two main models for the representation of spatial data in a GIS; they are the raster model and the vector model. MFworks uses the raster data model. Raster map layers are composed of an array or grid of square cells (these are similar to pixels). Each cell represents a square parcel of the real world. A value is assigned to each cell. The value represents an attribute of the real world parcel; for example: average elevation, number of voters, or soil type. Raster map layers are two dimensional Cartesian planes. Each cell has a row and column coordinate within that plane. That coordinate can be tied to real world coordinate systems such as Latitude & Longitude and UTM.

In the vector data model, maps are composed of objects that are represented by points, lines, and polygons that are referenced to real world objects using coordinate systems such as Latitude & Longitude and UTM. The Vector data model allows you to store topological information for each object. Topology is the mathematically explicit rules that govern the connections between spatial objects. The vector model is appropriate for the representation of discrete map objects. The primary limitation of the vector model is the inability to represent, analyse, and process continuous data such as aerial photographs, satellite images, and Digital Elevation Models (DEMs).

Why Use A Raster GIS?

The raster model lends itself well to portraying area based characteristics because its data structure, the cell, is area based. The size of the area represented by a cell is the cell resolution. In MFworks you can analyse and visualize spatial data with cell resolutions from millimetres to kilometres. The raster model is the best format for these applications:

• Slope
• Aspect
• Elevation
• Land Cover Types
  (e.g., Forest, Land Use)
• Remote Sensing
• Spatial image manipulation and enhancement
  (e.g.,satellite imagery, aerial photographs and scanned maps)
• Reflectance or brightness
• Modeling

The raster data model gives you superior analytical capabilities for continuous data and fast processing of map layer overlay operations. Rasterized spatial imagery is imported easily into MFworks for easy and extensive manipulation and enhancement. The raster model is not limited to the representation and manipulation of continuous data. It can also analyse discrete and linear features.

Raster GIS Users

Applications for raster GIS span a broad spectrum of organizations and fields. Since raster based GIS can complement and extend other forms of GIS, it can be used in any area where geographically enabled data is found. This might include such broad fields as:

Government	Educators (K-12, University)
Business	Resource managers
Researchers	Engineers
Urban & environmental planners	Consultants

MFworks and Raster GIS

MapFactory is a robust raster based GIS package that provides desktop computer users with powerful visualization, analysis, and mapping capabilities. It is an intuitive and highly productive software package that gives you the tools to solve practical problems. MFworks introduces an extensive suite of modelling and analysis tools for desktop computer users. It couples these tools with powerful mapping capabilities that can be used to create, modify, and view spatial data. MFworks's modular design allows you to develop custom applications for specific raster analysis, including:

thematic mapping	raster modeling
terrain analysis and processing	environmental mapping
spatial modeling	landscape architecture
image feature classification	viewshed analysis
predictive modeling	change detection

MFworks is based on the raster data model making it well suited for representing and processing geographic features that vary continuously over space such as: elevation, soil type, vegetation cover, slope, land use, surface aspect, population density, rainfall, and snow cover. MFworks can also be used to symbolize discrete, thematic, and discontinuous types of information such as: road networks, crop type, water quality samples, retail outlets, consumer behaviour, and a variety of demographic data. Use MFworks's extensive suite of operations to solve a wide range of spatial problems and produce high quality images to enhance reports, publications, and studies.

Advanced Analyses and Data Visualization

MFworks offers a sophisticated suite of operations for spatial analyses. MFworks has four types of operations: Neighbourhood, Overlay, Zonal, and Utility.

Operations can be called and executed in two ways: from the Operations menu or from the MFworks Script window. Selecting an operation from the Operations menu opens the dialog box for that operation. The Script window allows you to batch process map layers, write and execute spatial models, and record a sequence of map processing tasks.

Neighbourhood Operations

Neighbourhood operations assign values to cells based on the characteristics of the data within a specified distance of each cell. Neighbourhood operations include a number of distance and proximity functions that feature the ability to create buffers, calculate the cost based on distance, determine statistical summaries, determine slope and rates of change, interpolate a continuous data set from a sparse data set (e.g., GPS measurements), create shaded relief images, and perform edge detection and data smoothing.

Overlay Operations

Overlay operations are performed rapidly in MFworks, permitting the combination of multiple map layers for analysis and comparison. Overlay operations allow you to combine layers, mosaic layers, and perform layer cross tabulation.

Zonal Operations

Zonal operations allow you to manipulate specific map layer values (zones), perform efficient calculation of cell, zone, or polygon area and perimeter, reclassify map layer themes, and generate spatial statistics for specified polygons, zones, or areas.

Utility Operations

Utility operations enable you to change the cell resolution or map scale, extract portions of existing maps, rotate maps, or reduce the size of the data set for easier manipulation. The Utility operations allow you to take map layer data from many sources and adjust them so that they all have the same orientation, scale, and coverage.

Map Composition and Layout Facilities

The layout facility included in MFworks provides a user friendly method for the compilation of maps and legend elements for powerful output display of map analysis results. The drag and drop menu elements in the Layout window make it easy to add, modify and delete elements such as north arrows, scale bars, text labels, neat lines, graphics, grid overlay, and legend objects.

More Information on the MFworks Layout facilities.

File Translators for Data Integration

A wide array of translators is included with MFworks to enable you to import and/or export to other GIS software, including vector systems, desktop publishing software, and image manipulation software. The translators allow the integration of universal data formats into your project to provide a high degree of flexibility and compatibility. MFworks contains translators for the following data formats:

ARC/INFO (Import Results of Ungenerate)	MAP II (Freeware GIS)
Shapefile (ArcView .shp Files)	MIF/MID (MapInfo Interchange Format)
Binary (Raw Image Data)	TIFF/GeoTIFF (Tagged Image File Format)
BNA (Boundary Format)	TEXT (Tab Delimited Grid)
DEM (Digital Elevation Model)	TEXT (XYZ Point File)
DXF (Drawing eXchange Format)	PICT (Macintosh internal picture format)
SYmbolic LinK (SYLK - Spreadsheet)	BITMAP (Windows internal picture .bmp format)

More Information on the MFworks File Translation facilities.