From SwissExperiment

Web Data Access

Under SwissEx, we are trying to develop a system which uses the best technologies for the job. This not only means a variety of technologies for storing data, but also a variety of technologies for accessing data, depending on your situation. The idea behind all of these systems is that there will eventually be sufficient 'behind-the-scenes' integration that all data and metadata entered will be available using all the access methods provided. Each method has its own advantages.

Contents 1 Web Data Access 1.1 Geospatial data access 1.1.1 Microsoft SensorMap 1.1.2 GeoVITe 1.1.3 MediaWiki semantic maps 1.1.4 GSN web interface 1.2 Viewing data in a table 1.2.1 Streaming Data 1.2.2 Static data in the wiki 1.3 Plotting Data 1.3.1 Streaming Data 1.3.2 Static data in the wiki 1.4 Downloading data 1.4.1 GSN 1.4.2 SensorMap 1.4.3 GeoVITe 1.4.4 Wiki 1.5 Web services

Geospatial data access

We are currently developing three methods of accessing data geospatially. These interfaces do not store the data, but query it remotely.

Microsoft SensorMap

Sensors can be registered via the web interface or automatically registered via GSN:Home into the SensorMap interface. All locations and parameter names are publicly visible in this interface. Data can be public if desired or access can be granted on an individual basis. The main advantages of this platform are that it is: publicly accessible (hence provides good data mining possibilities); able to query, plot and compare multiple sensors from multiple servers; works autonomously.

GeoVITe

Due to licencing restrictions on the SwissTopo data, this system is only available within the ETH domain.
GeoVITe is a new WebGIS system written by the cartographic institute at ETHZ. Within this system (demo now available) you will be able to download both sensor information and the corresponding spatial static information from SwissTopo that you would find on GIS systems at Swiss academic institutions.

MediaWiki semantic maps

If you have accurate overhead imagery or maps, the MediaWiki semantic mappoint extension in the semantic mediawiki will allow you to provide georeferenced access to wiki information. This includes existing pages containing coordinate information. In this way, you can store GSN queries in a page (using the GSN query extension) along with any metadata and reference it in the map. This is particularly of use if you have high resolution maps (on the scale of meters) and closely spaced sensors. If you do not have high resolution images/maps, you can also use the googlemaps extension for the same purpose. Wannengrat:Home and its subsequent measurement locations are examples of how this can be achieved.

GSN web interface

The GSN web interface has very basic geospatial data mining capabilities via a variety of webmap software interfaces.

Viewing data in a table

Streaming Data

There are two methods of viewing data from GSN in a table:

• GSN web interface: All instances of GSN e.g. [1], have a web interface from where data can be queried and viewed in a table. A guide to the GSN web interface can be found in the GSN documentation.

• Wiki GSN query: Using the GSN query button, the GSN data can be queried from within the wiki and displayed as a table.

Static data in the wiki

Data stored using the semantic wiki, e.g. in the metadata database, can be queried using standard semantic wiki query language and displayed in a table. An example of this is the fieldsite database. The query corresponding to this table looks like this:

{{#ask:[[Category:Fieldsites]][[Deployment Name::+]][[Modification date::+]]|?Deployment Name|?Description|?Altitude land surface|?Organization|mainlabel=Fieldsite HomePage|format=table|limit=10000}}

This means: select all pages in the category 'Fieldsites' with any deployment name and modification date, and return the deployment name, description, altitude and organisation. Call it the Fieldsite HomePage, display it as a table with a maximum limit of 10000 lines.

Plotting Data

Streaming Data

Plotting streaming data is possible via the GSN web interface (see guide) or via Microsoft SensorMap (see guide.

• GSN: Using the GSN web interface, only data from the single GSN instance can be plotted, unless you import the data from another instance using the remote wrapper.
• SensorMap: Any sensor registered into the SensorMap interface can be plotted against any other.

Static data in the wiki

No extension currently exists in this wiki for plotting

Downloading data

Data can be downloaded through all of the interfaces.

GSN

The 'Data' tab in GSN provides the user with all the tools that they need to download data. Clicking on the first two horizontal bars ('Data Output' and 'Conditions') allows the user to specify the data required. The third horizontal bar ('Results') appears by default on the 'download' tab. Here the user has self explanatory options for data download and display.

SensorMap

By clicking on the individual sensors in the geospatial interface and selecting the time period using 'Time Traveller', the user can download everything presented in the plot with a single click. See the SensorMap user guide for more information.

GeoVITe

The GeoVITe download facility has yet to be defined. More will appear here once GeoVITe is fully available.

Wiki

The wiki can be used as a centralised interface for downloading information, whether it is stored in GSN or in the Semantic Wiki.

Data stored in GSN: There are two methods of downloading GSN data via the wiki:

• The first method uses one of two simple extensions to either present the latest data from a sensor or download a specified time period. The second of these extensions allows the user to store the query in a page, so that it can be accessed at any time.
• The first method allows the user to see the latest data or to download a specific time period, but does not allow one to download the latest x data points. For this, any complex query as described here can be stored in a page. This means that the data can be downloaded using a single click.

Example: http://montblanc.slf.ch:22001/multidata?nb=SPECIFIED&nb_value=10&vs%5B0%5D=wan3&field%5B0%5D=All&time_format=iso&download_format=csv&download_mode=inline

Provides this link: Latest 10 datapoints from all sensors on Wan3, Wannengrat

Data stored in the wiki: Data stored using the semantic wiki can be easily downloaded in the desired format by using a semantic wiki query such as the following:

{{#ask:[[Sample entry date::17-06-2008||18-06-2008]] [[Contact::User:Simone]] |?O2-Concentration |?Electric Conductivity |?Location |?Sample entry date |format=csv }}

Web services

For web services, see Application data access