foss relational database and geodatabase part ii ...zatelli/environmental_data... · foss...

Marco Ciolli, Dipartimento di Ingegneria Civile e Ambientale

FOSS Relational Database and GeoDatabase FOSS Relational Database and GeoDatabase

Part IIPart II

PostgreSQL, Data Base Open Source and GRASSPostgreSQL, Data Base Open Source and GRASSMarco Ciolli1 Fabio Zottele2

1DICAM Dipartimento di Ingegneria Civile Ambientale e Meccanica, Università di Trento

[email protected]

2 FEM Fondazione Mach, Centro Trasferimento Tecnologico

[email protected]

• DB management in GRASS may follow different procedures. • Procedures are not equivalent and the chice of a procedure provides

different data processing and analisys tools

In particular alphanumeric data connected to geographic data may be managed:

• Directly with GRASS DB engineThis option does not guarantee the respect of DBMS security functions (coherence, integrity and so on) file format is dbf

• Through an external DBMS interfaced with GRASS in different ways (directly, not directly)Data Management by means of an external Data Base is more reliable and improves analisys and processing capabilities

Here are various procedures regarding GRASS 6.2.x versions interfaced with PostgreSQL.


Data Base management in GRASS

Why an external DBMS is better?

Direct DB management with GRASS nay lead to:

• data redundance and inconsistency;

• data access concurrence problems (multi-user simultaneous access);

• lost of data integrity;

• security problems;

• performance problems under the point of view of time needed to:

- data search;

- data update.

A DBMS, is a tool designed expressely to manage archives, therefore is provided with all the instruments that are necessary and is flexible and tailorable.


Two interface types

GRASS and PostgreSQL interface can be obtained in two ways:

Direct Interface Interface through ODBC


GRASS

InterfaceGRASS/Postgres

PostgreSQL

GRASS

InterfaceGRASS/ODBC

PostgreSQLdriverODBC-

PostgreSQL

ODBC

https://grass.osgeo.org/grass74/manuals/database.html

GRASS can be connected to one or more database management systems (DBMS). db.* command set provides a base SQL support to manage attributes, while v.db.* command set operates with vector maps.

Some functions have been made available recently

* Categories: Category number is vector ID. It is used to connect the attribute/s

to each vector object. A vector object can have zero, one, two or more categories.

Category numbers are stored within geometry file and within attributes tablefor each

vector object (generally "cat" column).

Using v.category, category number can be printed or maintained. To connect a

vector object to many different tables, different category numbers for each vector

object are necessary.

* Layers: It is possible to connect geographical objects in a vector map to one

or more tables. Each “link” to a different attribute table is called “layer”. A link

defines which database driver, what database and which table must be used.

Each category number in a geometry file corresponds to a row in the attribute table

(generally “cat" column). Using v.db.connect layers can be listed or maintained.

GRASS layers does not contain geografic objects, but they are link to attribute

tables in which vector object can have zero, one or more categories.

If a vector object has zero categories in a layer, the result is it does not appear in the

layer.

In this way some vector objects can appear in some layers and not in other layers. The

advantage of this system is it allows to locate thematically different object that are

topologically related in a single map (for example forests and lakes, or cultivated areas

and water basins).

These virtual layers are also useful to connect temporal data series to series of objects

that does not change in time.

The first layer is active, for example the first table corresponds to the first layer.

Further tables are tied to following layers.

* SQL support: DBF driver provides a limited support to SQL while other

DBMS backends (PostgreSQL, MySQL ...) give full SQL support because

SQL commands are directly sent through DBMI.

SQL commands can be directly executed with db.execute, db.select and

other db.* modules.

When a new table is created, a new attribute table must be created and

must be populated with a row per each category (using v.to.db). This

operation can be performed in a single pass using v.db.addtable together

with type definition of table column.

db

Db commands and db interaction commands:

1. db.connect2. db.test3. db.drivers4. db.login

• DB connections:1. db.columns2. db.copy3. db.describe4. db.tables

5. db.execute6. db.select

• Tables:

• SQL query (operations on tables):

db.connect – allows the connection through a Dbm interface

db.test Tests db driver

to check function

db.drivers – Shows the available db driver list

db.login – Sets user and password of a certain db driver

db.columns – Allows to display columns of a certain table within a database

When database is connected and tables are visible it is posible to use graphic interface, more user friendly, to display the columns of a certain table in a database

db.copy – allows the user to copy a table between two database that maybe also connected through different db drivers

db.describe - Allows the user to display information about a table. If -c parameter is used only the names of the columns are obtained instead of complete description

db.tables - Fa la lista di tutte le tabelle contenute in un database

db.execute – executes SQL strings directly written or contained in a text file

db.select – Prints the result of a selection made in DataBase from an SQL string read from an input file or written in the

interface

Db commands and interaction vector-db:

commands v.db

1. v.db.connect2. v.to.db

3. v.db.update4. v.db.addtable5. v.db.droptable6. v.db.reconnect.all

• Vector-db connection:

1. Display Manager2. d.vect3. v.extract4. v.reclass

• SQL query:

v.db.connect - Prints or sets the

database connection for a particular vector

v.to.db – Allows to insert in a database data coming from a vector file

v.db.update - Allows to assign a new

value to a column connected to a certain

map

v.db.addtable – creates and adds a new

attributes table to a certain layer of an

existing vector map

v.db.droptable – removes attibutes table

of an exixting vector map

v.db.reconnect.all – reconnects vector

files to a new database

db.dropcol: Eliminates a column from a selcted attribute table

And:

db.in.ogr: Imports tables in various formats

db.out.ogr: Exports tables in various formats

Attributes table display from layer manager

It is possible to display the content of a table

connected to the displayed layer

Query from table manager

It is possible to create a

query directly from table

manager, in this case all Trentino SIC

with more than 4000 ha

surface

Query in table manager

It is possible to use query builder in table manager

Query in table manager

Add vector map layers in Table Manager

Delete layers in a vector map in Table Manager

Modify layers in a vector map in Table Manager

Manage tables in vector maps in Table Manager

Esecuting a query with d.vect

si richiede la visualizzazione delle

zone di censimento aventi area minore di

500000

Funziona con i monitor lanciati da d.mon

Esecuting a query with layer manager

SIC in Trentino with surface less than 4000 hectars

Esecuting a query with gis.m (tcltk - old)

Buildings in Trento with roof height less than 10 m

Esecuting a query with v.extract

Asks to create a new map containing only

streets in with emission between 8

and 9 in the morning is more than

5000 (g CO/km)

d.what.vect -help

Description: Allows the user to interactively query a vector map layer at user-selected locations within the current geographic region.

Usage: d.what.vect [-1txdfe] [map=name[,name,...]]

Flags: -1 Identify just one location -t Terse output. For parsing by programs. -x Print information as plain text to terminal window. -d Print topological information (debugging). -f Enable flashing (slower). -e Open form in edit mode.

Xterm: Vector -> Query with mouse (Form mode, editing enabled)

d.what.vect -e nomefile

Old interface d.m is still active can be invoked with: d.m&

It uses monitor x1, x2, x3

v.db.univar

v.db.join

v.db.renamecol

v.db.dropcol

http://pgdesigner.sourceforge.net/it/index.html

pgDesigner2

pgDesigner2

http://www.opengis.org/index.htm

http://mapserver.gis.umn.edu/

MapServer

http://ems-hitech.com/pgmanager/?src=overture

pgAdminIII

http://www.pgadmin.org/

http://www.pgadmin.org/

graphic interface for PostgreSQL written in Tcl/Tk, that allows the management of ana archive: table operations, queries....


PgAccess

http://sourceforge.net/projects/pgaccess

DBdesigner4

DBdesigner4 a tool to easily design data base (supports MySQL but, at the moment, not PostgreSQL)

DB-Designer Fork

DB Designer Fork is a fork of the fabFORCE DBDesigner 4. It integrates entity relationship design,front-end (you can run queries) and SQL exporting. DB Designer Fork generates SQL scripts

for Oracle, SQL Server, MySQL, FireBird, SQLite and PostgreSQL.

phpPgAdmin

http://grass.osgeo.org/wiki/Openoffice.org_with_SQL_Databases

http://dba.openoffice.org/

http://mdbtools.sourceforge.net/

Bibliografia• AA.VV.: "PostgreSQL Programmer's Guide", Regent of the University of California, 1995.

• AA.VV.: "PostgreSQL User's Guide", Regent of the University of California, 1995.

• V.S. Subrahmanian: “Principles of multimedia database system”, Morgan Kaufmann, 1998

• M. A. Brovelli, M. Negretti, C. Saldarini: “GRASS interfacing with DBMSs”, Geomatics Workbooks

• Indexing tree methods and spatial ordering for maps and geographic data: an overview and application to the geodetic gis project, atti del congresso ISPRS - WG VI/3 "International cooperation and technology transfert", Parma, 15-19 febbraio 1999 L. Biagi, M. A. Brovelli, M. Negretti and C. Saldarini;• Nuove metodologie GIS per la stima e l’aggiornamento del geoide, pp.123-165, tesi di Laurea svolta presso il Politecnico di Milano, 1999, M. Negretti, C.Saldarini.• Ciolli M. Dispense del Corso GRASS e OPEN SOURCE GIS teoria ed applicazioni 1a edizione - anno 2003, 2a edizione - anno 2004, 3a edizione - anno 2005, 4a edizione - Roma anno 2006, 5a edizione Trento anno 2006, 6a edizione Trento anno 2007,7a edizione Trento anno 2008, 8a edizione Trento anno 2009,. • File sorgenti e manuali di PostgreSQL: http://www.postgresql.org e http://techdocs.postgresql.org/

• Interfaccia grafica PgAccess: http://www.flex.ro/pgaccess/ e www.pgaccess.org

• File sorgenti e manuali di GRASS: http://grass.itc.it/

• http://www.html.it/sql

•Suffritti P., Appunti sui DataBase Relazionali e sul linguaggio SQL. http://www.suffritti.it/SQLTutorial.htm

• L.Biagi, M.A.Brovelli, M.Negretti, Caratteristiche di PostgreSQL http://www.geo.unipr.it/~gis/TUTORIALS/POSTGRESINTRO/postgres.pdf

•M. Zanoni, Implementazione di un sistema integrato gis–database per la gestione dei dati di traffico e produzione di mappe delle emissioni. applicazione alla città di Trento. Tesi di Laurea Ingegneria Trento 2003

•C. Modena, Analisi e delimitazione delle aree forestali con particolare funzione protettiva in Trentino tramite tecniche GIS. Tesi di Laurea Ingegneria Trento 2003

•A. Daloli, Strutturazione e sviluppo di un Database in Postgresql per l’analisi dei dati di traffico Tesi di Laurea, Ingegneria Trento 2002

•All the web sites cited in this document must be considered part of this bibliography list.Marco Ciolli, Dipartimento di Ingegneria Civile e Ambientale

http://www.flex.ro/pgaccess/

http://www.pgaccess.org/

http://grass.itc.it/

http://www.html.it/sql

http://www.geo.unipr.it/~gis/TUTORIALS/POSTGRESINTRO/postgres.pdf

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