Grass

Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Grass shopping experience:

1. Compare - without doubt the biggest advantage that the Grass offers shoppers today is the ability to compare thousands of Grass at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Grass? Wrong! If the Grass is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Grass then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Grass? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Grass and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Grass wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Grass then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Grass site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Grass, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Grass, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

{{Infobox_Software | name = GRASS | logo = ] | screenshot = ] | caption = [Quantum GIS browser with GRASS GIS support. | developer = [GRASS Development Team | latest_release_version = 6.2.2 | latest_release_date = July 16, [ | operating_system = [Linux, [Microsoft Windows, [Mac OS X, [POSIX compliant systems | genre = [Geographic information system | license = [GNU General Public License | website = http://grass.itc.it | -->

GRASS (Geographic Resources Analysis Support System) is an open source, Free Software Geographic information system (GIS) with raster, topological vector (spatial), image processing, and computer graphics production functionality that operates on various computer platform through a graphical user interface and shell (computing) in the X Window System. It is released under GNU General Public License (GPL).

The recent GRASS 6 release introduces a new topological 2D/3D vector engine and support for vector network analysis. Attributes are managed in dBASE files or SQL-based DBMS such as MySQL, PostgreSQL/PostGIS, and SQLite. The system is capable of visualizing 3D computer graphics vector graphics data and voxel volumes. GRASS supports an extensive range of raster and vector formats through the binding to GDAL, including OGC-conformal (Open Geospatial Consortium) Simple Features for interoperability with other GIS. It also supports Linear Reference System.

The GRASS Development Team is a multi-national group consisting of developers at numerous locations. GRASS is one of the eight initial Software Projects of the Open Source Geospatial Foundation.

Architecture GRASS supports raster and vector data in two and three dimensions. The vector data model is Topology, meaning that areas are defined by boundaries and centroids; boundaries cannot overlap within a single layer. This is in contrast with OpenGIS Simple Features, which define vectors more freely, much as a non-georeferenced vector illustration program does.

GRASS is designed as an environment in which tools that perform specific GIS computations are executed. Unlike typical application software, upon starting GRASS, the user is presented with a UNIX shell containing a modified environment that supports the execution of GRASS commands (known as modules). The environment has a state that includes such parameters as the geographic region covered and the map projection in use. All GRASS modules read this state and additionally are given specific parameters (such as input and output maps, or values to use in a computation) when executed. The majority of GRASS modules and capabilities can be operated via a graphical user interface (provided by a GRASS module), as an alternative to manipulating geographic data in shell. There are over 200 core GRASS modules included in the GRASS distribution, and over 100 add-on modules created by users and offered on the GRASS web site. The GRASS libraries and core modules are written in C (programming language); other modules are written in C, UNIX shell, Tcl, or other scripting languages. The GRASS modules are designed under the Unix philosophy and hence can be combined using shell scripting to create more complex or specialized modules by a user without knowledge of C programming.

There is cooperation between GRASS and Quantum GIS (QGIS). Recent versions of QGIS can be executed within the GRASS environment, allowing QGIS to be used as a user-friendly graphical interface to GRASS that more closely resembles other graphical GIS software than does the unique shell-based GRASS interface. See the screenshot for an example.

There also exists a project to re-implement GRASS in Java (Sun) as JGRASS.

History GRASS (Geographic Resources Analysis Support System) GRASS has been under continuous development since 1982 and has involved a large number of federal US agencies, universities, and private companies. The core components of GRASS and the management of the integration efforts into GRASS releases were accomplished by the U.S. Army - Construction Engineering Research Laboratory (USA-CERL) in Champaign, Illinois. USA-CERL completed its last release of GRASS as version 4.1 in 1992, and provided five updates and patches to this release through 1995. USA-CERL also wrote the core components of the GRASS 5.0 floating point version.

The development of GRASS was begun by the U.S. Army Corp of Engineering Research Laboratory (USA-CERL) in Champaign, Illinois, a branch of the U.S. Army Corps of Engineers to meet the need of the United States military for software for land management and environmental planning.An key motivation was the National Environmental Policy Act. The development platform was UNIX running on VAX hardware. During 1982 through 1995, USA-CERL led the development of GRASS, with the involvement of numerous others, including universities and other federal agencies. USA-CERL officially ceased its involvement in GRASS after release 4.1 (1995), though development had been limited to minor patches since 1993. A group formed at Baylor University to take over the software, releasing GRASS 4.2. Around this period, the license of the originally public-domain GRASS software was changed to the GNU GPL and a port of the software to Linux was made. In 1998, Markus Neteler, the current project leader, announced the release of GRASS 4.2.1, which offered major improvements including a new graphical user interface.GRASS Developent Team. GRASS History. Retrieved on 2007-07-11.

Subsequently, GRASS has evolved into a powerful software suite with a wide range of applications in many different areas of scientific research.GRASS is currently used in academic and commercial settings around the world, as well as many governmental agencies including NASA, NOAA, United States Department of Agriculture, German Aerospace Center, CSIRO, the National Park Service, the U.S. Census Bureau, USGS, and many environmental consulting companies.

GRASS development is split into a stable branch (6.2) and a development branch (6.3). The stable branch is recommended for most users, while the 6.3 branch operates as a testbed for new features.

References

Bibliography

Neteler, M. and H. Mitasova "Open Source GIS: A GRASS GIS Approach. Second Edition." Boston: Kluwer Academic Publishers/Springer. 424pp, 2004. ISBN

1-4020-8064-6, Online Supplement

GDF Hannover bR: GRASS GIS 6.0 Tutorial, Version 1.2, 2005, Online Supplement
Indian Example PDF download
A.P. Pradeepkumar (2003) "Absolute Beginners Guide to Linux/GRASS installation" Online publication at GRASS Development Project Website In English available at http://grass.itc.it/gdp/tutorial/abs_beginners.pdf
原著 A. P. Pradeepkumar (2003) GRASS 5.00 安装新手指南 in Chinese available at http://www.cngis.org/archive/opensource/attach/GRASS%205%20%B0%B2%D7%B0%D0%C2%CA%D6%D6%B8%C4%CF.pdf