Pasquale Di Donato p1d1d1

Virtual layer for SWISSIMAGE

Go to https://www.swisstopo.admin.ch/en/geodata/images/ortho/swissimage10.html#download
Choose a selection mode (rectangle, polygon, municipality, ...)
Set your options, click on search, click on export all link and download the CSV file
Prefix each URL in the CSV file with the string "/vsicurl/"
Run

gdalbuildvrt -input_file_list yourDownloadedFile.csv yourOutputFile.vrt

GeoSPARQL support: Triple Stores comparison

I have been planning since months to put in a readable form some tests I did to check how Triple Stores deal with GeoSPARQL. Then a twitter discussion has eventually given me the motivation to start these notes. The word "benchmarking" I used in the mentioned twitter discussion is actually not the right one. It is not my intention to measure performance (how quick is the store to load data, how many trillions triples are managed, how fast is the response to a federated query over tens services): my main interest here is simply to load some geodata and run a basic GeoSPARQL query and see how the stores behave. I decided to use docker and run the images with the default configurations available in Docker Hub: sometimes I have quikly further investigated in case of failure.

Dataset

For the tests I used a simple dataset containing the 26 Swiss Ca

	<?xml version="1.0" encoding="UTF-8"?>
	<kml xmlns="http://earth.google.com/kml/2.0">
	<!-- Comment: see http://www.keyhole.com/kml/kml_doc.html for file definition... -->
	<Document>
	<name>OziExplorer Data</name>
	<visibility>1</visibility>
	<LookAt>
	<longitude>8.432598308622</longitude>
	<latitude>45.919633714058</latitude>
	<range>10000</range>

	{
	"type": "Feature",
	"bbox": [
	669243.9209251693,
	223895.80049622757,
	716899.6020993304,
	283343.19079530047
	],
	"id": 1,
	"properties": {

	{
	"feature": {
	"layerBodId": "ch.swisstopo.swissboundaries3d-kanton-flaeche.fill",
	"featureId": 1,
	"properties": {
	"ak": "ZH",
	"label": "Zürich",
	"name": "Zürich",
	"flaeche": 172894
	},

	PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
	PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
	PREFIX wdt: <http://www.wikidata.org/prop/direct/>
	PREFIX wikibase: <http://wikiba.se/ontology#>
	PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
	PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
	PREFIX wd: <http://www.wikidata.org/entity/>
	PREFIX fn: <http://www.w3.org/2005/xpath-functions#>
	PREFIX geo: <http://www.opengis.net/ont/geosparql#>

	PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
	PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
	PREFIX wdt: <http://www.wikidata.org/prop/direct/>
	PREFIX wikibase: <http://wikiba.se/ontology#>
	PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
	PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
	PREFIX wd: <http://www.wikidata.org/entity/>
	PREFIX fn: <http://www.w3.org/2005/xpath-functions#>
	PREFIX geo: <http://www.opengis.net/ont/geosparql#>