COMPUTER TOOLS
For the creation and editing of the Observatory data The following tools are used.
A. Database
For the organization, storage and management of data used PostgreSQL is installed on Linux Server (Ubuntu Server 14.04)
PostgreSQL is an open source relational database with many capabilities. The development lasted for over two decades and is based on a well proven architecture that has created a strong perception of about the credibility of users, data integrity and proper operation.
Some of the key features are
- ANSI SQL 89, 92, 93
- 100% compatible with ACID and full support commit and rollback.
- Online backups: higher security and data availability.
- Data types: numeric, decimal, smallint, integer, bigint, real, double, serial, char, varchar, bit, text, date, time, timestamp, interval, boolean, network address, geometric types and more.
- Ability to create new types of data by users.
- Save BLOBS (binary large objects), including text, audio, images or video.
- Full support aggregate functions (GROUP_BY) as COUNT, SUM, AVG, MIN, MAX, STDDEV and VARIANCE. Ability to create new aggregate functions if necessary.
- Support all types of compounds (cross, inner, outer, left, right, full, natural).
- Some functions from the user, which can be written in many programming languages such as C, SQL, PL / pgSQL, TCL, Perl, Python, Ruby.
programming language development environment - Library functions and operators with some preinstalled functions such as math, date / time, string, geometric, formating etc.
- Trigger functions can be set from any programming language that supports o server as C or PL / pgQL.
- Temporary tables are automatically deleted after the end of the session.
- Model group / user safety. Access to the database server can be limited by the user, host or database.
- The size of the table and the database is almost unlimited. Unlimited entries and indexes per table
B. Spatial Database
To create and edit spatial data used the extension of the PostgreSQL PostGIS.
The PostGIS spatially enables the PostgreSQL, allowing it to be used as database in Geographic Information Systems (GIS) and web mapping applications.
The PostGIS is stable, fast, compatible with international standards, provides hundreds of spatial functions and is the most popular at the moment open source spatial database. The PostGIS is used by diverse organizations around the world, including high-risk government agencies and organizations storing data terabytes and serving millions of online calls per day.
The management of the database is including via pgAdmin and phpPgAdmin. The input and output data provided by various conversion tools (shp2pgsql, pgsql2shp, ogr2ogr, dxf2postgis). And there are many GIS software (desktop and online) for data overview in PostGIS.
Key Features of PostGIS are:
- spatial functions
- spatial analysis tools such as: influence zones, union, intersection, attack, distance, and more
- Complete ACID transactions
- Spatial R-Tree lists
- Support for multiple simultaneous users
- Lock line level
- copy capability
- sealing
- Security based roles
- tables seating, base shapes
- Implemented Standards
- Compatible with the OGC standards (SFSQL)
C. GIS Software
1. pgRouting
The pgRouting extends geospatial PostGIS / PostgreSQL database adding routing capabilities.
The pgRouting provides features such as:
- Dikstra route: routing algorithm with heuristics
- A-Star: routing for large databases (with heuristics)
- Shooting-Star: Routing restrictions in speed (with heuristics)
- The Traveling Salesman Problem (TSP)
- Calculation of driving distance (Isolines)
2. QGIS
The QGIS is an open source GIS software, user friendly, which can be viewed, management, processing, analysis and map composition. It incorporates powerful analytical capabilities via integration with the GRASS. It can run on Linux, Unix, Mac OSX, and Windows. Supports multiple vector, raster file formats, multiple database types and corresponding functionality for them.
Key Features QGIS is:
- GUI interface.
- Identification and selection of features,
- processing / visualization / search descriptive characteristics,
- Immediate change projector,
- print composer,
- characteristic symbols,
- Symbol changes for vector and raster data,
- adding new levels,
- Easily preview numerous vector and raster models of digital files
- Tables base PostgreSQL / PostGIS data
- Support for most vector models: including ESRI shapefiles, MapInfo, SDTS and GML.
- Support for raster data such as Digital Terrain Models, aerial photographs and satellite images,
- Standards Support GRASS,
- reader support online viewing and downloading services of OGC (WMS or WFS);
- Create, edit and export spatial data using: digitizing tools of GRASS and shapefile standard, The additional georeferencing (plugin), GPS tools to import and export GPX files, the transformation from other GPS models in GPX, or upload files directly to a GPS receiver
- Performing spatial analyzes with additional fTools and GRASS
- Algebra maps
- landscape analysis,
- Hydrological modeling,
- Network Analysis,
- Publication on the Internet
- Architecture with additives (plugins).
- Compatible with the standards of OGC (WMS, WFS)