FOSS Relational Database and GeoDatabase Part II. PostgreSQL, Data Base Open Source and GRASS. Marco Ciolli, Fabio Zottele

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1 FOSS Relational Database and GeoDatabase Part II PostgreSQL, Data Base Open Source and GRASS Marco Ciolli, Fabio Zottele Dipartimento di Ingegneria Civile e Ambientale Universita' degli Studi di Trento Marco Ciolli, Dipartimento di Ingegneria Civile e Ambientale

2 Data Base management in GRASS 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 engine This 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 various procedures regarding GRASS 6.2.x versions interfaced with PostgreSQL. Marco Ciolli, Dipartimento di Ingegneria Civile e Ambientale

3 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. Marco Ciolli, Dipartimento di Ingegneria Civile e Ambientale

4 Two interface types GRASS and PostgreSQL interface can be obtained in two ways: Direct Interface Interface through ODBC GRASS GRASS Interfaccia GRASS/Postgres Interfaccia GRASS/ODBC PostgreSQL PostgreSQL Marco Ciolli, Dipartimento di Ingegneria Civile e Ambientale ODBC driver ODBCPostgreSQL

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6 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.

7 Some functions have been made available recently

8 * Categorie: 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.

9 * 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.

10 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.

11 * 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.

12 Db commands and db interaction commands: comandi db DB connections: 1. db.connect 2. db.test 3. db.drivers 4. db.login Tables: 1. db.columns 2. db.copy 3. db.describe 4. db.tables SQL query (operations on tables): db.execute db.select

13 db.connect allows the connection through a Dbm interface

14 db.test Tests db driver to check function

15 db.drivers Shows the available db driver list

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

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

18 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

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

20 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

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

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

23 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

24 Db commands and interaction vector-db: comandi v.db Vector-db connection: SQL query: v.db.connect v.to.db v.db.update v.db.addtable v.db.droptable v.db.reconnect.all Display Manager d.vect v.extract v.reclass

25 v.db.connect Prints or sets the database connection for a particular vector

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

27 v.db.update Allows to assign a new value to a column connected to a certain map

28 v.db.addtable creates and adds a new attributes table to a certain layer of an existing vector map

29 v.db.droptable removes attibutes table of an exixting vector map

30 v.db.reconnect.all reconnects vector files to a new database

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

32 And: db.in.ogr: Imports tables in various formats db.out.ogr: Exports tables in various formats

33 Attributes table display from layer manager It is possible to display the content of a table connected to the displayed layer

34 Query from table manager It is possible to create a query direcly form table manager, in this case all Trentino SIC with more than 4000 ha surface

35 Query in table manager It is possible to use query builder in table manager

36 Query in table manager

37 Add vector map layers in Table Manager

38 Delete layers in a vector map in Table Manager

39 Modify layers in a vector map in Table Manager

40 Manage tables in vector maps in Table Manager

41 Esecuting a query with d.vect si richiede la visualizzazione delle zone di censimento aventi area minore di Funziona con i monitor lanciati da d.mon

42 Esecuting a query with layer manager SIC in Trentino with surface less than 4000 hectars

43 Esecuting a query with gis.m (tcltk - old) Buildings in Trento with roof height less than 10 m

44 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)

45 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.

46 Xterm: Vector -> Query with mouse (Form mode, editing enabled) d.what.vect -e nomefile

47 Old interface d.m is still active can be invoked with: d.m& It uses monitor x1, x2, x3

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50 v.db.univar

51 v.db.join

52 v.db.renamecol

53 v.db.dropcol

54 pgdesigner

55 pgdesigner

56 pgdesigner

57 MapServer

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59 pgadminiii

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61 PgAccess graphic interface for PostgreSQL written in Tcl/Tk, that allows the management of ana archive: table operations, queries... Marco Ciolli, Dipartimento di Ingegneria Civile e Ambientale

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63 Marco Ciolli, Dipartimento di Ingegneria Civile e Ambientale

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

65 phppgadmin

66 phppgadmin

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74 Bibliografia AA.VV.: "PostgreSQL Programmer's Guide", Regent of the University of California, AA.VV.: "PostgreSQL User's Guide", Regent of the University of California, 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, febbraio 1999 L. Biagi, M. A. Brovelli, M. Negretti and C. Saldarini; Nuove metodologie GIS per la stima e l aggiornamento del geoide, pp , 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: e Interfaccia grafica PgAccess: e File sorgenti e manuali di GRASS: Suffritti P., Appunti sui DataBase Relazionali e sul linguaggio SQL. L.Biagi, M.A.Brovelli, M.Negretti, Caratteristiche di PostgreSQL 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