Difference between revisions of "TerraHS"

Revision as of 18:56, 24 November 2009

What is it ?

is a software component that enables the development of geographical applications in a functional language, using the data handling capabilities of TerraLib. TerraLib is a C++ library that supports different spatial database management systems, and that includes a large number of spatial algorithms. As a result, we get a combination of the good features of both programming paradigms.

Developing geographic information systems is a complex task. GIS applications involve data handling, algorithms, spatial data modeling, spatial ontology and user interfaces. The diversity of structures such as networks, fields, objects, time series and spatial temporal data types , is an intimidating problem for GIS developers.

Research in Geographic Information Science has shown that many spatial data can be expressed as algebraic theories. These algebraic theories formalize spatial components in a rigorous and generic way. As an answer to the challenges of translation of algebraic specifications into computer languages, there has been a growing interest in functional languages. So, the TerraHS is an application development system that enables prototyping novel GisScience ideas in Haskell.

Features

The major features are:

Input and output formats: Layers or themes from TerraLib databases (just MySQL), Esri Shape File (*.shp), TIFF file.
Data types: Raster or image (just 8 bits), Vectors (Point, Line, Polygon and Cell), Temporal (DateTime, Interval)
Topological operators: intersects, within, touches, crosses ...
Geometric operations: intersection, union, difference, rotation.
Metrical operations: perimeter, area, distance, centroid, shapeindex, compacity, fractal

Demos

The following figure is one example of a vector data can be exported to a TerraLib database, and then it can be visualized with TerraView.

The pattern for a main program in TerraHS has the folowing structure:

module Main(main) where

import TerraHS

host = "localhost";
dbname =  "demo_terrahs";
user = "root";
password = "root";

main:: IO()
main = do
	-- loading a vector data from a shape file
	gos <- loadVectorFile "MG_MUN96.shp"
	-- open a connection
	db <- open (TeMySQL host user password dbname)
	-- saving in a database layer
	store db "layer_name" gos
	print "saved"

Two different outcomes from a image data and theirs respective operations (a)input image, (b) inverted image and (c) reverse image.

The following examples use this data:

Its possible to run in the ghci:

 #ghci SpatialOper.hs

printing some test values, e.g.:

 Main> main
 Loading package syb ... linking ... done.
 Loading package base-3.0.3.0 ... linking ... done.
 Loading package terrahs-0.8 ... linking ... done.
 TePoint (12.5,10.0)
 TeLine2D [(1.0,1.0),(1.0,2.0),(1.0,7.0)]
 TePolygon [TeLine2D [(1.0,1.0),(1.0,2.0),(3.0,2.0),(3.0,1.0),(1.0,1.0)]]
 False
 True
 False
 2.0

or compile and run:

#ghc SpatialOper.hs -package terrahs-0.8 -o main
#main

More details about the api in source documentation - online (HTML)

Download and Installation

TerraHS is available in cabal package from Hackage. See How to install a Cabal package in Linux or Windows.

Installation notes for Linux

Software dependencies in debian package

The installation procedure:

 #sudo dpkg -i package.deb

The uninstallation procedure:

 #sudo dpkg -r package

Software dependencies in source file

The installation procedure:

#tar xvzf package.tar.gz
#cd package
#./configure
#make
#sudo make install

The uninstallation procedure:

 #cd package
 #sudo make uninstall

Installation notes for Windows

Coming soon

Software dependencies

TerraHS is a Haskell GIS application built using the TerraLib GIS library. In below, is available a debian packages for TerraLib. TerraHS-0.8 uses the TerraLib-3.3.0 version.

TerraLib-3.3.0 for (Ubuntu 9.04 (x86))

Optional, but is recommended to install the TerraView application.TerraView is a GIS application based on TerraLib, a GIS library to handle vector and raster data in geographical DBMS such as Access, PostgreSQL, MySQL and Oracle Spatial.

TerraView-3.3.0 for (Ubuntu 9.04 (x86))

The TerraLib and TerraView source files can be downloaded from official sites:

TerraLib
TerraView.

We have developed some specific libraries to support some functionalities for TerraHS. The libraries can be installed from an unique package (TerraLib4c+Translib)

TerraHSdependecies for Ubuntu 9.04 (x86)

Or can be download in separated way:

Translib, a library for translation among different geographic format files (no database connection), based in the TerraLib library. This library is required for TerraHS to deal whith shape files (*.shp).

Ubuntu 9.04 (x86)

Source, generic Linux

Terralib4c, a library that maps c++ Terralib functions and classes to C functions. Required by Haskell to do binding with TerraLib api.