Freeware for GIS and Remote Sensing

Education in remote sensing and GIS is based on software utilization. The software needs to be installed in computer rooms with a certain number of licenses. The commercial software equipment is therefore financially demanding and not only for universities, but especially for students. Internet research brings a long list of free software of various capabilities. The paper shows a present state of GIS, image processing and remote sensing free software.


Introduction
GIS and remote sensing tasks are mutually interlinked and division of software to GIS software and remote sensing software means that GIS software is able to work with remote sensing data and to perform simple tasks with them.On the contrary, GIS functions are embedded in remote sensing software.This duality is a result of close relation between these regions.Looking for the GIS free software, three groups of them can be found Viewers of commercial software -ArcReader 91 , ArcExplorer 4.02 of ESRI, GeoMedia® Viewer of INTERGRAPH, FreeLook 3.13 for ENVI, etc.
Software tools for certain tasks as GDAL 1.1.5[11], libgeotiff, MB-System4 for bathymetry and backscatter imagery data derived from multibeam, interferometry, and sidescan sonars, MITAB5 MITAB a C++ library for reading and writing MapInfo .TAB (binary) and .MIF/MID files.
Complete GIS software -GRASS, ILWIS, FMaps covering GIS together with remote sensing.

Freeware for GIS and Remote Sensing
Software for image processing -Intel, Image Analyzer 1.27 The Open Source GIS [7] brings a list of more than 150 free GIS software available for users.The web page remotesensing.org[15] is a source of many free software for remote sensing including the link to Remote Sensing Tutorial prepared by William J. Campbell from NASA [10].

Viewers of commercial software
Following examples shows limits of viewers for common users.[13].Key Features of the software are data access providing read-only access to geospatial data in Microsoft Access, MapInfo and Shapefile formats.With GeoMedia Viewer new connections to the above formats can be also created if you have other data sets you want to access.GeoMedia Viewer let us create new geoworkspaces and save any changes made to existing geoworkspaces.GeoMedia Viewer includes a powerful set of navigation commands for moving around and exploring your data as Pan, Zooming, etc. and supports multiple windows including map and data windows.

GeoMedia extregistered Viewer
ArcExplorer [9].As a complete data explorer, ArcExplorer -Java lets display and query a wide variety of standard data sources.Using ArcExplorer as a stand-alone desktop application, it is possible to consume shapefiles, a variety of images, ArcSDE layers, and more, allows to also pan and zoom through these map layers and identify, locate, and query their spatial and attribute information.You can buffer a selected set of features and view their attributes.ArcExplorer also provides the ability to thematically map your data, symbolizing various features based upon information found in the data's attribute table, displaying graduated symbology, or classbreaks rendering for instance.

Software tools for certain tasks
There are many software packages for large number of different tasks and questions for GIS purposes [6].Project conversion software form an important group of them.GDAL 1.1.5[11] is a translator library for raster geospatial data formats.As a library, it presents a single abstract data model to the calling application for all supported formats.A initial skeleton of GDAL has formed, and operates for a few formats [11].
Geotiff libs [16] -GeoTIFF represents an effort by over 160 different remote sensing, GIS, cartographic, and surveying related companies and organizations to establish a TIFF6 based interchange format for georeferenced raster imagery [16].Virtual Terrain Project [17] -The goal of VTP is to foster the creation of tools for easily constructing any part of the real world in interactive, 3D digital form.This goal will require a synergetic convergence of the fields of CAD, GIS, visual simulation, surveying and remote sensing.VTP gathers information and tracks progress in areas such as procedural scene construction, feature extraction, and rendering algorithms.VTP writes and supports a set of software tools, including an interactive runtime environment (VTP Enviro).The tools and their source code are freely shared7 to help accelerate the adoption and development of the necessary technologies [15].

Complete GIS/remote sensing software
There are four useful GIS and remote sensing free software packages -GRASS, ILWIS, OSSIM and FMaps.
GRASS -Geographic Resources Analysis Support System commonly referred to as GRASS, this is a Geographic Information System (GIS) used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization.GRASS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies.GRASS is a raster GIS.There are a large range of applications of GRASS: geography, landscape ecology, epidemiology, remote sensing8 , urban planning, biology, geophysics, hydrology, groundwater Flow Modeling (GRASS and MODFLOW9 ), vector network analysis (in part of GRASS 610 ), geostatistics11 , raster 3D Volume12 (voxel) [5].FMaps [5] is an open source GIS/RS (Geographic Information System/ Remote Sensing) application on the Linux 13 and Gnome 14 compatible platforms.The database engine is Post-greSQL 15 .PostgreSQL is an opensource SQL server.
OSSIM (Open Source Software Image Map) [14] is a high performance software system for remote sensing, image processing, geographical information systems and photogrammetry.It is an open source software project maintained at http://www.ossim.organd has been under active development since 1996.The lead developers for the project have years of experience in commercial and government remote sensing systems and applications.OSSIM has been funded by several US government agencies in the intelligence and defense community and the technology is currently deployed in research and operational sites.The name OSSIM is a contrived acronym (Open Source Software Image Map) that is pronounced "awesome"the acronym was established by our first government customer.Designed as a series of high performance software libraries it is written in C++ employing the latest techniques in object oriented software design.A number of command line utilities, GUI tools and applications, and integrated systems have been implemented with the baseline.Many of those tools and applications are included with the software releases.
MultiSpec is a freeware multispectral image data analysis system (latest release: 5-12-2007) MultiSpec is being developed at Purdue University

Conclusion
There are more viewers belonging to the software group.Viewers are tools for ready data and users with low level of demands and are prepared for large society of users and created by commercial GIS/remote sensing companies.They are in fact useless for most processing of advanced users and students.The software packages focused on certain tasks are useful for solution of individual problems which cannot be processed in other software on one side or for solution of stand alone tasks.Their application for education of GIS or remote sensing as a whole is not suitable.The university education of GIS and remote sensing can be based on complete software like GRASS and others.The open software allows to use existing modules PROJ 4.4.3[8] -This package offers command line tools and a library for performing respective forward and inverse transformation of cartographic data to or from cartesian data with a wide range of selectable projection functions.O.S. GNU/Linux and other Unices Windows [8].

ILWIS [ 1
] version 3.4.is a software created for Windows platform and the following list shows the product tools: Integrated raster and vector design Import and export of widely used data formats On-screen and tablet digitizing Comprehensive set of image processing tools Orthophoto, image georeferencing, transformation and mosaicing Advanced modeling and spatial data analysis 3D visualization with interactive editing for optimal view findings Rich projection and coordinate system library Geo-statistical analyses, with Kriging for improved interpolation Production and visualization of stereo image pairs Spatial Multiple Criteria Evaluation 52°North Initiative for Geospatial Open Source Software GmbH is an international research and development company whose mission is to promote the conception, development and application of free open source geo-software for research, education, training and practical use.52°North backs an open initiative, which is driven by leading research organizations and individuals in the international GIS field.The work of all partners results in a collection of Java based web services implementations [1].
16, West Lafayette 17 , IN18, by David Landgrebe19and Larry Biehl 20 from the School of Electrical and Computer Engineering 21 , ITaP 22 and LARS23.It results from an on-going multiyear research effort which is intended to define robust and fundamentally based technology for analyzing multispectral and hyperspectral image data, and to transfer this technology to the user community in as rapid a manner as possible.The results of the research are implemented into MultiSpec and made available to the user community via the download pages.MultiSpec© with its documentation© is distributed without charge.TheIntel software covers wide range of image processing methods applicable in remote sensing and other branches.The largest user group can be found among digital photographs users.ImageAnalyzer 1.27.[6] is a freeware for Windows 98/ME/2000/XP/Vista.Advanced image editing, enhancement and analysis software.The program contains both most image enhancement features found in conventional image editors plus a number of advanced features not even available in professional photo suites as: Automatic brightness, contrast, gamma and saturation adjustment Build-in conventional and adaptive filters for noise reduction, edge extraction etc. Math expression module for creating and transforming images and advanced "pocket" calculator with equation solver Plugin system for adding more specialized features.See below for available plugins