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LOBOViz CGI Data Service

The LOBOViz server has a public CGI (Common Gateway Interface) that allows remote clients to request and receive LOBO sensor data via HTTP (Hyper-Text Transfer Protocol). This page describes how to access the CGI and retrieve sensor data.

CGI URL

The LOBOViz data CGI for this server is published at the following URL:

  • http://tulane.loboviz.com/cgi-bin/nph-data.cgi

CGI Data Query Parameters

Parameters are appended to the URL after a '?' character and are each is subsequently separated by a '&' character.

The following common parameters are supported:

ParameterDescription
min_datefirst day of data query in format [YYYYMMDD]
max_datelast day of data query in format [YYYYMMDD]
ycomma-separated list of measurement names for dependent variable(s)
data_formatrequired to be 'text' for text output

Rather than specific min_date and max_date, there are two alternate date selectors:

ParameterDescription
days=nthe most recent n days from today
newest=nthe most recent n measurements

The following are examples of commonly used measurement names for the 'y=' independent variable list:

NameDescription
cdomcolored dissolved organic matter
conductivityconductivity
oxygendissolved oxygen
fluorescencefluorescence
nitratenitrate concentration
oxygen_satoxygen saturation
voltagepower supply voltage
salinitysalinity
scatteringscattering coeff
temperaturewater temperature
turbidityturbidity

The names of other measurement items and node identifiers can be found by examining the URL after producing a plot then using the Permalink button. Users with full management access can list all items in the system configuration tools. Note that only one node may be selected per data download.

ParameterDescription
nodesite selection

As mentioned above for measurement names; use the Permalink URL from a plot to determine the numeric site identification for use in the value of a "node=" parameter. Note that unlike data plots which can display multiple sites simultaneously, data download is one site at a time.

CGI Data Result Format

The data are returned as tab-separated text representations of numeric values. The first line of the returned data is a header of tab separated names and units for each data column. Each subsequent line displays local date/time in format [YYYY-MM-DD hh:mm:ss], followed by a numeric value for each requested measurement.

Example

For example, if you want to retrieve salinity and nitrate for July 28, 2016 to August 2, 2016 (inclusive) at the example site the URL would be:

http://tulane.loboviz.com/cgi-data/nph-data.cgi?min_date=20160628&max_date=20160702&y=salinity,nitrate&data_format=text&node=53

Click the above URL to see the tab-separated text data returned by the server.

Another example, the 12 most recent temperature measurements:

http://tulane.loboviz.com/cgi-data/nph-data.cgi?newest=12&y=temperature&data_format=text&node=53

Scripted Usage

Any programming language with HTTP support can be used to directly access the LOBO data CGI and process the returned sensor measurements. Alternately, an HTTP utility such as wget can be invoked to retrieve the data and save to local file for later processing.