Visualization APIs

The out-of-the-box visualization APIs dispatch to opencpu in order to generate statistical plots using R. When a request is sent to a visualization API, it is proxied by ohmage to opencpu. opencpu then calls back into ohmage and uses survey_response/read to retrieve data to plot.

• Survey Response Count Visualization
• Survey Response Count by Privacy State Visualization
• Survey Response Count by Privacy State Time Series Visualization
• Prompt Distribution Visualization
• Prompt Time Series Visualization
• User Time Series Visualization
• Scatter Plot Visualization
• 2D Density Visualization
• 2D Density Visualization

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Survey Response Count Visualization

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What does it do?

Returns a PNG image showing the number of survey responses for a particular survey.

URI

/app/viz/survey_response_count/read

Access Rules

TODO

Input Parameters

• (r) auth_token = The authentication token for the requester.
• (r) campaign_urn = The URN of the campaign whose aggregated survey response count you desire.
• (r) width = The desired width of the resulting image.
• (r) height = The desired height of the resulting image.
• (o) privacy_state = "shared" to plot only shared responses.
• (o) start_date = A start date for the time range of the request. It must be of the format "yyyy-MM-dd".
• (o) end_date = A end date for the time range of the request. It must be of the format "yyyy-MM-dd".

Example POST

POST /app/image/read HTTP/1.1
 Host: dev.ohmage.org
 Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.77 Safari/535.7
 Content-Length: byte-length-of-content
 Content-Type: application/x-www-form-urlencoded

  auth_token=384j4fj-sj4j-w84fh984-sj9sj
  &campaign_urn=urn:some:campaign
  &width=800
  &height=600
  &privacy_state=shared

Output Format

Success

The requested plot is returned as an PNG image in the HTTP stream.

Failure

See the error page for a description of error codes and their associated descriptions.

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