Strabon
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| author | Dimitris Bilidas <d.bilidas@di.uoa.gr> |
|---|---|
| date | Mon Nov 09 18:09:06 2020 +0200 (2020-11-09) |
| parents | b87735624a1c |
| children | 5b6b65340693 |
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1 Strabon
2 -----------
4 Introduction
5 ============
6 Strabon is a fully implemented semantic geospatial database system that can be
7 used to store linked geospatial data expressed in RDF and query them using an
8 extension of SPARQL. Strabon supports spatial selections, spatial joins, a rich
9 set of spatial functions similar to those offered by geospatial relational
10 database systems, support for multiple Coordinate Reference Systems and widely
11 used serializations for geometric objects such as WKT and GML. Strabon is built
12 on top of the well-known RDF store Sesame and extends Sesame’s components to be
13 able to manage thematic and spatial data that are stored in PostGIS.
15 The development of Strabon started in the context of European FP7 project
16 SemsorGrid4Env (Semantic Sensor Grids for Rapid Application Development for
17 Environmental Management) [http://www.semsorgrid4env.eu/]. Starting September
18 2011, Strabon is being utilized and extended with new functionalities in the
19 FP7 project TELEIOS (Virtual Observatory Infrastructure for Earth Observation
20 Data) [http://www.earthobservatory.eu/] which our group leads.
22 The query language of Strabon is called stSPARQL. stSPARQL can be used to query
23 data represented in an extension of RDF called stRDF. stRDF and stSPARQL have
24 been designed for representing and querying geospatial data that changes over
25 time (e.g., the growth of a city over the years due to new developments).
27 Currently, only the geospatial features of stSPARQL have been implemented fully.
28 The temporal features are the subject of current work.
30 Given the very close relationship between stSPARQL and GeoSPARQL which is a
31 recent OGC standard for an extension of SPARQL for querying geospatial metadata,
32 we recently provided support for the Core, Geometry and Geometry Topology
33 extension of GeoSPARQL.
36 Conformance to GeoSPARQL
37 ========================
38 Strabon implements the `Core', the `Topology Vocabulary Extension', the
39 `Geometry Extension', the `Geometry Topology Extension', and the `RDFS Entailment
40 Extension' except for Req. 25
41 (http://www.opengis.net/spec/geosparql/1.0/req/rdfs-entailment-extension/bgp-rdfs-ent).
43 With respect to GML, Strabon supports the GML Profile corresponding to Simple
44 Features, that is, GML Simple Features Profile 2.0.
47 Strabon Homepage
48 ================
49 The homepage of Strabon is at http://www.strabon.di.uoa.gr/.
52 Demo
53 ====
54 You can find a demo of the system Strabon at http://test.strabon.di.uoa.gr/NOA/.
57 How to build and run Strabon from command line
58 ==============================================
59 Assuming you have already downloaded Strabon and you are in the top-level
60 directory of Strabon, issue the following command to build it from command line:
62 $ mvn clean package
64 In order to run automatically the JUnit tests, pass the option `-DskipTests=false'
65 to the above command. The complete command is the following:
67 $ mvn -DskipTests=false clean package
69 Alternatively, it is possible to run a specific test. Supposing that the name of
70 the corresponding class is `TestName', then you can run only this
71 test using the following command:
73 $ mvn test -DfailIfNoTests=false -DskipTests=false -Dtest=TestName
75 In case of an error during building of Strabon and assuming that the error does
76 not come from the JUnit tests, please have a look at the `Known Issues' section
77 below. If none of the known issues of that section applies, please contact the
78 developers through the Strabon mailing-list or submit a corresponding bug
79 (see `Bugs' section below).
81 After you have successfully built Strabon, you have access to the following
82 components:
84 * Strabon Endpoint
86 This is a SPARQL endpoint for Strabon. It is distributed as a war file so
87 you may deploy it in a Tomcat container. You may find the war file under
88 directory `endpoint/target'.
90 * Strabon Endpoint (standalone)
92 This is a SPARQL endpoint for Strabon like the above one, but it differs
93 only in that it does not require the user to have already set up a Tomcat
94 container. The standalone Strabon Endpoint may be run by issuing the
95 following command:
97 $ java -jar endpoint-exec/target/strabon-endpoint-executable-${version}.jar
99 After issuing the above command, you may access the Strabon Endpoint at
100 the following URL: <http://localhost:8080/>.
102 Please see the page at <http://hg.strabon.di.uoa.gr/Strabon/rev/674f8f91162b>
103 to find out other options that you may pass to the Tomcat container that
104 will run by the above command.
106 SPECIAL NOTE: if you need to configure the connection details to the
107 underlying database, you may do so in two ways:
108 1. By modifying file `endpoint/WebContent/WEB-INF/connection.properties'
109 before building Strabon and executing the above command.
110 2. After executing the above command, by visiting the following page by a
111 browser: <http://localhost:8080/ChangeConnection>
113 * Strabon Endpoint Client
115 This is a Java client for interacting with Strabon Endpoint or any other
116 SPARQL endpoint. It is packaged as a jar file and may be found under
117 directory `endpoint-client/target/' with name
118 `strabon-endpoint-client-${version}.jar'. This jar contains any dependencies
119 to other code, so may copy and paste it to your project and start playing
120 with the code immediately.
122 * Strabon script
124 The `strabon' script is located under the `scripts/' directory and it is the
125 main command-line tool for interacting with Strabon. You may use it to store
126 RDF data with geospatial information or query/update it using one of
127 stSPARQL or GeoSPARQL query languages.
129 * Endpoint script
131 The `endpoint' script is located under the `scripts' directory and it is the
132 main command-line tool for interacting with a `Strabon Endpoint'. You may
133 use it to do any operation you would like to do with the `strabon' script
134 above, but in contrast to the `strabon' script you need to have access to a
135 Strabon endpoint. Of course, the `Strabon Endpoint Client' component above
136 can be used as well as a command-line tool. At the time of writing, the
137 `Strabon Endpoint Client' component supports only querying of RDF data with
138 geospatial information.
141 Getting Started
142 ===============
143 To get started with Strabon please have a look at the tutorial for the stRDF
144 data model and stSPARQL query language, the User Guide, and the Developer Guide.
146 stRDF and stSPARQL tutorial
147 http://www.strabon.di.uoa.gr/files/stSPARQL_tutorial.pdf
150 stSPARQL Reference
151 ~~~~~~~~~~~~~~~~~~
152 The reference for the spatial and temporal extension functions defined in
153 stSPARQL can be found at http://www.strabon.di.uoa.gr/stSPARQL#spatial and
154 http://www.strabon.di.uoa.gr/stSPARQL#temporals respectively.
157 User Guide
158 ~~~~~~~~~~
159 Assuming that you are familiar with Maven, the following steps need to be
160 followed in order to use Strabon using Eclipse:
162 1. Install PostgreSQL from http://www.postgresql.org/download/. At the time of
163 this writing the latest PostgreSQL version is 9.1.
164 2. Install PostGIS from http://postgis.refractions.net/download/. At the time of
165 this writing we have tested Strabon with PostGIS 1.5.3.
166 3. Install Maven from http://maven.apache.org/download.html. At the time of this
167 writing the latest Maven version is 3.0.4.
168 4. Install Eclipse from http://www.eclipse.org/downloads/. At the time of this
169 writing the latest Eclipse version is 3.7.2.
170 5. Install the m2e plugin for Eclipse from http://www.eclipse.org/m2e/.
171 6. Install the MercurialEclipse plugin for Eclipse from
172 http://javaforge.com/project/HGE .
173 7. From Eclipse, go to File --> Import --> Mercurial --> Clone Existing
174 Mercurial Repository --> Next. In the URL textarea paste the following
175 URL: http://hg.strabon.di.uoa.gr/StrabonUser and then press Next --> Next -->
176 Finish. If you used the default settings, you should have a new project named
177 StrabonMain. Right click on the project and select Configure --> Convert to
178 Maven project. Eclipse will enable Maven dependency management for the
179 project, download any dependencies and build the project.
182 Storing stRDF graphs and evaluating stSPARQL queries
183 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
184 You can see some examples in the classes gr.uoa.di.strabon.example.PostgisExample
185 and gr.uoa.di.strabon.example.PostgisExample2.
187 Tuning PostgreSQL
188 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
189 The default settings of Postgres are rather conservative. As a result, parameter
190 tuning is neccessary for speeding up Postgres, therefore Strabon. If you are
191 using Strabon to compare its performance against your implementation of
192 stSPARQL/GeoSPARQL, you are *strongly* encouraged to contact us using the Strabon
193 Users mailing list for assistance on tuning Postgres.
195 You can follow the instructions below for tuning a Postgres server running on an
196 Ubuntu machine that is dedicated to PostgreSQL and Strabon.
198 1. Append the following text at the end of postgresql.conf.
199 *Uncomment* the appropriate lines.
201 ### RAM
202 ## 4 GB of RAM
203 #shared_buffers = 3GB
204 #effective_cache_size = 3GB
205 #maintenance_work_mem = 1GB
206 #work_mem = 2GB
207 ## 8 GB of RAM
208 #shared_buffers = 5GB
209 #effective_cache_size = 6GB
210 #maintenance_work_mem = 2GB
211 #work_mem = 5GB
212 ## 16 GB of RAM
213 #shared_buffers = 10GB
214 #effective_cache_size = 14GB
215 #maintenance_work_mem = 4GB
216 #work_mem = 10GB
217 ## 24 GB of RAM
218 #shared_buffers = 16GB
219 #effective_cache_size = 22GB
220 #maintenance_work_mem = 6GB
221 #work_mem = 15GB
222 ## 48 GB of RAM
223 #shared_buffers = 32GB
224 #effective_cache_size = 46GB
225 #maintenance_work_mem = 8GB
226 #work_mem = 30GB
227 ## 64 GB of RAM
228 # contact us to find out!
229 ### HD
230 ## RAID with ordinary 7.200 disks
231 #random_page_cost = 3.5 #3.0-3.5
232 ## High-End NAS/SAN
233 #random_page_cost = 2 #1.5-2.5
234 ## Amazon EBS/Heroku
235 #random_page_cost = 1.3 #1.1-2.0
236 ## SSD array
237 #random_page_cost = 2.0 #1.5-2.5
238 ### Planner options
239 # Increase the following values in order to avoid using the GEQO planner.
240 # Small values (<8) reduce planning time but may produce inferior query plans
241 #
242 geqo_threshold = 15 # keep this value larger that the following two parameters
243 from_collapse_limit = 14
244 join_collapse_limit = 14
245 ### Misc
246 default_statistics_target = 10000
247 constraint_exclusion = on
248 checkpoint_completion_target = 0.9
249 wal_buffers = 32MB
250 checkpoint_segments = 64
251 ### Connections
252 max_connections = 10
254 2. Append the following lines at the end of /etc/sysctl.conf
255 *Uncomment* the appropriate lines.
257 ## 4 GB of RAM
258 #kernel.shmmax = 3758096384
259 #kernel.shmall = 3758096384
260 #kernel.shmmni = 4096
261 ## 8 GB of RAM
262 #kernel.shmmax = 5905580032
263 #kernel.shmall = 5905580032
264 #kernel.shmmni = 4096
265 ## 16 GB of RAM
266 #kernel.shmmax = 11274289152
267 #kernel.shmall = 11274289152
268 #kernel.shmmni = 4096
269 ## 24 GB of RAM
270 #kernel.shmmax = 17716740096
271 #kernel.shmall = 17716740096
272 #kernel.shmmni = 4096
273 ## 48 GB of RAM
274 #kernel.shmmax = 35433480192
275 #kernel.shmall = 35433480192
276 #kernel.shmmni = 4224
277 ## 64 GB of RAM
278 # contact us to find out!
280 3. Apply all changes by executing
282 $ sudo sysctl -p
283 $ sudo /etc/init.d/postgresql restart
285 4. Prepare for the next run by issuing the command
287 $ sudo -u postgres psql -c 'VACUUM ANALYZE;' db
289 or
291 $ psql -c 'VACUUM ANALYZE;' db
293 where db is the name of the Postgres database that Strabon will use.
296 Developer Guide
297 ~~~~~~~~~~~~~~~
298 Assuming that you are familiar with Maven, the following steps need to be
299 followed in order to use Strabon using Eclipse:
301 1. Install PostgreSQL from http://www.postgresql.org/download/. At the time of
302 this writing the latest PostgreSQL version is 9.1.
303 2. Install PostGIS from http://postgis.refractions.net/download/. At the time of
304 this writing we have tested Strabon with PostGIS 1.5.3.
305 3. Install Maven from http://maven.apache.org/download.html. At the time of this
306 writing the latest Maven version is 3.0.4.
307 4. Install Eclipse from http://www.eclipse.org/downloads/. At the time of this
308 writing the latest Eclipse version is 3.7.2.
309 5. Install the m2e plugin for Eclipse from http://www.eclipse.org/m2e/.
310 6. Install the MercurialEclipse plugin for Eclipse from
311 http://javaforge.com/project/HGE.
312 7. From Eclipse, go to File --> Import --> Mercurial --> Clone Existing
313 Mercurial Repository --> Next. In the URL textarea paste the following
314 URL: http://hg.strabon.di.uoa.gr/Strabon and then press Next --> Next -->
315 Finish. If you used the default settings, you should have a new project named
316 StrabonMain. Right click on the project and select Configure --> Convert to
317 Maven project. Eclipse will enable Maven dependency management for the
318 project, download any dependencies and build the project.
321 Tester Guide
322 ~~~~~~~~~~~~
323 Assuming again that you are familiar with Maven and Junit these are the steps
324 you need to follow to test the functionality of Strabon:
327 * Using Eclipse
329 If you want to create a new test:
331 1. Import Strabon into Eclipse as explained in the Developer Guide.
332 2. Go to strabon-testsuite project.
333 3. Create a new folder (Recommended folder name: <test's name>) and place inside the following files:
334 3.1. An ntriples or nquads file with the test dataset (with .nt or .nq extension).
335 3.2. Pairs of files with sparql test queries and expected test results in xml format.
336 Notice that each pair must have the same name and .rq extension for the queryFile and .srx extension for the resultsFile.
337 4. Create a test class that extends TemplateTest class.
338 5. If you have followed the recommendations the test is ready. If you have different names or location for your
339 files, insert them explicitly in the constructor of the class. WARNING: All prefixes must be placed in file "prefixes" so that
340 every time a namespace changes, we have to change it just once.
342 If you want to run a test:
344 1. Right-click on the test class.
345 2. Select "Run as JUnit Test".
346 3. Database properties are retrieved from database.properties file. If you want, you can change a property
347 "on the fly" with an environment variable.
350 * Command Line
352 If you want to run all the tests:
354 1. Go to Strabon directory (root directory of all the subprojects).
355 2. Run "mvn test -DskipTests=false".
356 3. Optionally you can pass an environment variable with "-DvariableName=variableValue".
359 Storing stRDF graphs and evaluating stSPARQL queries
360 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
361 You can see some examples in the classes
362 eu.earthobservatory.runtime.postgis.StoreOp and
363 eu.earthobservatory.runtime.postgis.QueryOp.
366 Download
367 ========
368 You can download the source code of the latest version of Strabon by accessing
369 our public mercurial repository located at http://hg.strabon.di.uoa.gr/Strabon.
370 You can find more information on how to use and extend Strabon at the Getting
371 Started section.
374 Publications
375 ============
376 You can learn about stRDF data model and stSPARQL query language employed in
377 Strabon by reading our tutorial under the Getting Started section and/or the
378 publications given on this page.
380 The current versions of stRDF and stSPARQL which are based on OGC standards are
381 presented in the following document:
382 * K. Kyzirakos, M. Karpathiotakis, and M. Koubarakis. Strabon: A Semantic
383 Geospatial DBMS. In Internatioanl Semantic Web Conference (ISWC'12). Boston,
384 USA, November 11-15, 2012.
385 [pdf: http://strabon.di.uoa.gr/files/strabon-iswc.pdf]
387 * Manolis Koubarakis, Kostis Kyzirakos, Babis Nikolaou, Michael Sioutis, and
388 Stavros Vassos. A data model and query language for an extension of RDF with
389 time and space. Deliverable D2.1, European ICT project TELEIOS, 2011.
390 [pdf: http://strabon.di.uoa.gr/files/deliv2-1-re-revised.pdf]
392 The initial versions of stRDF and stSPARQL that are based on constraint
393 databases are presented in the following publications:
394 * Manolis Koubarakis and Kostis Kyzirakos. Modeling and Querying Metadata in
395 the Semantic Sensor Web: the Model stRDF and the Query Language stSPARQL.
396 In 7th Extended Semantic Web Conference (ESWC 2010). Heraklion, Crete,
397 30 May - 03 June, 2010.
398 [pdf: http://strabon.di.uoa.gr/files/stSPARQL.pdf]
400 * Kostis Kyzirakos, Manos Karpathiotakis and Manolis Koubarakis. Developing
401 Registries for the Semantic Sensor Web using stRDF and stSPARQL (short
402 paper).
403 In Proceedings of 3rd International workshop on Semantic Sensor Networks
404 2010, in conjunction with ISWC 2010, November 2010, Shanghai, China.
405 [pdf: http://strabon.di.uoa.gr/files/strabon.pdf]
407 Applications of stRDF, stSPARQL, and the system Strabon are described here:
408 * Alasdair J. G. Gray, Raúl García-Castro, Kostis Kyzirakos, Manos
409 Karpathiotakis, Jean-Paul Calbimonte, Kevin Page, Jason Sadler, Alex
410 Frazer, Ixent Galpin, Alvaro A. A. Fernandes, Norman W. Paton, Oscar
411 Corcho, Manolis Koubarakis, David De Roure, Kirk Martinez and Asunción
412 Gómez-Pérez. A Semantically Enabled Service Architecture for Mashups over
413 Streaming and Stored Data. In 8th Extended Semantic Web Conference (ESWC
414 2011). Heraklion, Crete, May 20 - June 2, 2011.
415 [pdf: http://strabon.di.uoa.gr/files/Gray2011Architecture.pdf]
417 * A.J.G. Gray, J. Sadler, O. Kit, K. Kyzirakos, M. Karpathiotakis, J.-P.
418 Calbimonte, K. Page, R. García-Castro, A. Frazer, I. Galpin, A.A.A.
419 Fernandes, N.W. Paton, O. Corcho, M. Koubarakis, D.D. Roure, K. Martinez,
420 A. Gómez-Pérez. A Semantic Sensor Web for Environmental Decision Support
421 Applications. Sensors. 11, 8855-8887.
422 [pdf: http://strabon.di.uoa.gr/files/sensors-11-08855.pdf]
424 Coming up soon:
425 Strabon will soon support an extension of RDF for incomplete geospatial
426 information. The following publication gives a preview of the relevant research
427 problems:
428 * M. Koubarakis, K. Kyzirakos, M. Karpathiotakis, C. Nikolaou, M. Sioutis,
429 S. Vassos, D. Michail, T. Herekakis, C. Kontoes and I. Papoutsis. Challenges
430 for Qualitative Spatial Reasoning in Linked Geospatial Data. In Proceedings
431 of IJCAI 2011 Workshop on Benchmarks and Applications of Spatial Reasoning,
432 Barcelona, Spain.
433 [pdf: http://www.earthobservatory.eu/publications/SciQL_ADASS2011.pdf]
435 * C. Nikolaou and M. Koubarakis: "Querying Linked Geospatial Data with
436 Incomplete Information". In 5th International Terra Cognita Workshop -
437 Foundations, Technologies and Applications of the Geospatial Web. In
438 conjunction with the 11th International Semantic Web Conference, Boston,
439 USA, November, 2012.
440 [http://www.earthobservatory.eu/publications/iswc-workshop.pdf]
443 Contributors
444 ============
445 The system Strabon has been developed by the following members of our team:
447 * Manos Karpathiotakis <mk@di.uoa.gr>
448 * Kostis Kyzirakos <Kostis.Kyzirakos@cwi.nl>
449 * Manolis Koubarakis <koubarak@di.uoa.gr>
450 * Giorgos Garbis <ggarbis@di.uoa.gr>
451 * Konstantina Bereta <konstantina.bereta@di.uoa.gr>
452 * Charalampos Nikolaou <charnik@di.uoa.gr>
453 * Stella Gianakopoulou <sgian@di.uoa.gr>
454 * Panayiotis Smeros <psmeros@di.uoa.gr>
455 * Kallirroi Dogani <kallirroi@di.uoa.gr>
458 Mailing-list
459 ============
460 Currently, we maintain the following mailing lists:
462 * Strabon-users, is used as a communication channel for Strabon users.
463 To subscribe to the mailing-list, please visit page
464 http://cgi.di.uoa.gr/~mailman/listinfo/strabon-users. To post e-mails
465 to Strabon-users mailing-list, write to strabon-users@di.uoa.gr.
467 * Strabon-devel, is used as a communication channel with the developers
468 of Strabon. To subscribe to the mailing-list, please visit page
469 http://cgi.di.uoa.gr/~mailman/listinfo/strabon-devel. To post e-mails
470 to Strabon-devel mailing-list, write to strabon-devel@di.uoa.gr.
473 Bugs
474 ====
475 Please report bugs to http://bug.strabon.di.uoa.gr/report or
476 the Strabon-devel mailing-list Strabon-devel@di.uoa.gr.
479 Known Issues
480 ============
481 * By default, Tomcat uses ISO-8859-1 character encoding when decoding URLs received
482 from a browser. This can cause problems when encoding is UTF-8, and you are using
483 international characters. In order to fix this, edit conf/server.xml and find the
484 line where the Connector is defined. Add the parameter URIEncoding and set it to
485 UTF-8. For example:
487 <Connector port="8080" protocol="HTTP/1.1"
488 connectionTimeout="20000"
489 URIEncoding="UTF-8"
490 redirectPort="8443" />
492 * Building and executing any maven goals fails for maven versions <3.0 due to a
493 dependency to the `shade' plugin that is available only for maven version 3.0
494 (http://maven.apache.org/plugins/maven-shade-plugin/). In such systems, you may
495 disable execution of this plugin by setting the environmental variable
496 `shade.skip'. For example, to build Strabon using maven version 2.0 you may
497 execute the following command:
499 $ mvn clean package -Dshade.skip
501 * When using MonetDB as a backend, the following source code of MonetDB must be
502 used:
503 https://hg.strabon.di.uoa.gr/MonetDB/
506 License
507 =======
508 This Source Code Form is subject to the terms of the Mozilla Public
509 License, v. 2.0. If a copy of the MPL was not distributed with this
510 file, You can obtain one at http://mozilla.org/MPL/2.0/.
512 Copyright (C) 2010, 2011, 2012, Pyravlos Team
514 http://www.strabon.di.uoa.gr/
517 How to apply the license
518 ========================
519 * In the beginning of script files (after the shell directive) paste the
520 following statement:
521 #
522 # This Source Code Form is subject to the terms of the Mozilla Public
523 # License, v. 2.0. If a copy of the MPL was not distributed with this
524 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
525 #
526 # Copyright (C) 2010, 2011, 2012, Pyravlos Team
527 #
528 # http://www.strabon.di.uoa.gr/
529 #
531 * In the beginning of Java source code files paste the following statement:
532 /**
533 * This Source Code Form is subject to the terms of the Mozilla Public
534 * License, v. 2.0. If a copy of the MPL was not distributed with this
535 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
536 *
537 * Copyright (C) 2010, 2011, 2012, Pyravlos Team
538 *
539 * http://www.strabon.di.uoa.gr/
540 */
542 * In the beginning of HTML/XML files paste the following statement:
543 <!-- This Source Code Form is subject to the terms of the Mozilla Public
544 - License, v. 2.0. If a copy of the MPL was not distributed with this
545 - file, You can obtain one at http://mozilla.org/MPL/2.0/.
546 -
547 - Copyright (C) 2010, 2011, 2012, Pyravlos Team
548 -
549 - http://www.strabon.di.uoa.gr/
550 -->