Frequently Asked Questions
Frequently Asked Questions. A list of questions and answers commonly used on the web to provide the same information to many users.
The study of the earth and its features and of the distribution of life on the earth, including human life and the effects of human activity.
The measurement or acquisition of information of an object or phenomenon, by a recording device that is not in physical or intimate contact with the object. Data may be acquired through a variety of devices depending upon the object or phenomina being observed.
A geographic information system (GIS) is an organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information. GIS is distinguished from other information system technology in its ability to perform common database operations and statistical analysis, as well as complex visualization and geographic analysis. These unique capabilities make GIS valuable for explaining events, predicting outcomes, and planning strategies.
.E00 are ARC/INFO Export files, or interchange files, that can be used to transport coverages, INFO data files, text files such as AML macros, and other ARC/INFO files between various machine types. An interchange file contains all coverage information and appropriate INFO data file information in a fixed-length ASCII format.
A vector data storage format for storing the location, shape, and attributes of geographic features. A shapefile is stored in a set of related files and contains one feature class.
A vector file is a data storage format for storing the location, shape, and attributes of geographic features. A shapefile is stored in a set of related files and contains one feature class.
An abstraction of the real world where spatial data is expressed as a matrix of cells or pixels, with spatial position implicit in the ordering of the pixels. With the raster data model, spatial data is not continuous but divided into discrete units. This makes raster data particularly suitable for certain types of spatial operation.
ESRI (pronounced either EZZ-ree or EE-ESS-AHR-EYE, its employees only call it EE-ESS-AHR-EYE, though) abbreviates the name of Environmental Systems Research Institute, Inc., an organization based in Redlands, California which produces Geographic Information System software. They are the largest manufacturers and sellers of geographic information systems in the world with large offices in both the U.S. and UK and smaller offices elsewhere. ESRI uses the name, ArcGIS to refer to its suite of GIS software products, which operate on desktop, server, and mobile platforms. ArcGIS also includes developer products and web services. This is the main GIS software package that MARIS uses on a daily basis.
The leading provider of Geographic Imaging products and related services to clients worldwide. ERDAS' business encompasses software development, sales, technical support and training for numerous geographic imaging products, custom applications development and project consulting services. The software runs on the most popular platforms: Windows and UNIX. The products are tightly integrated, highly customizable, and easy-to-learn-and-use.
MrSID is an acronym for Multi-resolution Seamless Image Database. More information is available at LizardTech.
TIFF is a tag-based image file format that is designed to promote the interchange of digital image data. The TIFF format originated in 1986 when Aldus Corporation and leading scanner vendors worked together to create a standard file format for images used in desktop publishing. The first version of the specification was published in July, 1986. Version 6.0 of the specification was completed in September, 1995, and is available on Adobe's Web site. TIFF provides a general purpose data format and is compatible with a wide range of scanners and image-processing applications. It is device independent and is used in most operating environments, including Windows, Macintosh, and UNIX. This non-proprietary industry standard for data communication has been implemented by most scanner manufacturers and desktop publishing applications. Adobe continues to evaluate and incorporate TIFF enhancements that are useful within publishing applications, maintaining backward compatibility whenever possible (e.g., even applications written in the fall of 1986 can read many modern TIFF 6.0-compatible images).
Data used with geographic information technology have different characteristics than data required in conventional data base systems. GIS uses spatial data which, quite simply, includes anything that takes up geographic space or has geographic distribution.
MARIS maintains vector and raster data. The vector data is organized
into two distinct ways:
Raster data is avaible either by county or selected areas.
- Statewide Files -indicates the extent of the themes area of
coverage is continuous over the whole state.
- County Files - the themes area of coverage exists by individual
counties for each county in the state.
A mathematical formula that transforms feature locations from the earth’s curved surface to a map’s flat surface. A projected coordinate system employs a projection to transform locations expressed as latitude and longitude values to x,y coordinates. Projections cause distortions in one or more of these spatial properties: distance, area, shape, and direction.
MARIS uses the Mississippi Transverse Mercator (MSTM) projection.
The MARIS Technical Center (MTC) and the Mississippi Department of Transportation (MDOT) jointly developed a map projection for Mississippi called the Mississippi Transverse Mercator (MSTM) Projection. When viewing geographic data on a statewide level, the MSTM projection alleviates the multiple-zone conflict inherent in UTM and State Plane systems.The problem with both of these systems is that each divides the state into an east and west zone that cannot be digitally displayed together.
The MSTM projection is a customized Transverse Mercator projection designed to more evenly distribute convergence and scale-factor, and is based on the North American Datum of 1983 (NAD83). The projection parameters of the MSTM projection are as follows:
Central Meridian: -89 45' 00''
Central Latitude: 32 30' 00''
False Northing: 1,300,000 meters
False Easting: 500,000 meters
Projection Units: meters
This projection is used by both MTC and MDOT for the development and storage of geographic data. The MTC can and does receive and distribute data in a number of other projections, however, the MARIS Technical Center and MDOT encourage the use of the MSTM projection.
More information regarding the development of the MSTM projection and its projection parameters may be obtained by contacting MARIS at 601-432-6128.