--- title: "Visitor Tracking Parameters - SDC" slug: "visitor-tracking-parameters-sdc" updated: 2020-04-16T20:44:25Z published: 2020-04-16T20:44:25Z canonical: "onpremises.webtrends.help/visitor-tracking-parameters-sdc" --- > ## Documentation Index > Fetch the complete documentation index at: https://onpremises.webtrends.help/llms.txt > Use this file to discover all available pages before exploring further. # Visitor Tracking Parameters - SDC Visitor Tracking parameters allow you to track daily, weekly, monthly, quarterly, and yearly unique visitors. The Smartsource Data Collector (SDC) inserts these parameters into the cs-uri-query strings. #### WT.vt_tlv `WT.vt_tlv=UNIX Time` SDC generates this parameter to identify the time of the visitor’s last visit. The value is expressed as the number of seconds since 1970 (standard UNIX time), which is calculated using information stored in the third-party cookie value. SDC only sets this parameter at the start of a new visit. On a visitor’s first visit, the value is set to zero. If you disable cookie tracking, this parameter is not generated or passed in the query string. Note Visitor Data Mart uses this query parameter to determine whether a new visit should also be counted as a new daily, weekly, monthly, quarterly, or yearly visitor. For example, if the day of the new visit is different than the day of the previous visit, relative to the GMT offset of the JavaScript tag, the visit is counted as a new daily visit. #### WT.vt_f_tlv `WT.vt_f_tlv=UNIX Time` SDC generates this parameter to identify the time of the visitor’s last visit. The value is expressed as the number of seconds since 1970 (standard UNIX time), which is calculated using information stored in the first-party cookie value. SDC only sets this parameter at the start of a new visit. On a visitor’s first visit, the value is set to zero. If you disable first-party cookie tracking in the JavaScript tag, this parameter is not generated or passed in the query string. Note Visitor Data Mart uses this query parameter to determine whether a new visit should also be counted as a new daily, weekly, monthly, quarterly, or yearly visitor. For example, if the day of the new visit is different than the day of the previous visit, relative to the GMT offset of the JavaScript tag, the visit is counted as a new daily visit. #### WT.vt_d `WT.vt_d=1` SDC generates this parameter to track daily visitors for Express Analysis. This parameter is generated and set to 1 for the first hit from a new visitor for a day. #### WT.vt_a_d `WT.vt_d=1` SDC generates this parameter to track daily visitors for Account Rollup Data Sources. This parameter is generated and set to 1 for the first hit from a new visitor for a day for a given account. This parameter is used in conjunction with Account Rollup Profiles. #### WT.vt_f_d `WT.vt_f_d=1` SDC generates this parameter to track daily visitors for Express Analysis only. This parameter is generated and set to 1 for the first hit from a new visitor when you configure your SmartSource Data Source to use the First-Party Cookie JavaScript. The First-Party Cookie JavaScript generates this parameter and its value. #### WT.vt_s `WT.vt_s=1` SDC generates this parameter to track visitor sessions for Express Analysis and Visitor Data Mart. This parameter is generated and set to 1 for the first hit for a new session. Cookie tracking must be enabled to set this query parameter. #### WT.vt_a_s `WT.vt_a_s=1` SDC generates this parameter to track visitor sessions for Account Rollup Data Sources. Applies to Real Time analysis only. This parameter is generated and set to 1 for the first hit for a new session for a given account. This parameter is used in conjunction with Account Rollup Profiles. #### WT.vt_f_s `WT.vt_f_s=1` SDC generates this parameter to track new visitor sessions for Express Analysis and Webtrends Visitor Data Mart. This parameter is generated and set to 1 for the first hit for a new session. The First-Party Cookie JavaScript generates this parameter. #### WT.vt_f `WT.vt_f=1` SDC generates this parameter to track new and returning visitors. This parameter is generated and set to 1 for the first hit from a new visitor. This parameter is set to 2 if the visitor’s browser does not accept cookies. The First-Party Cookie JavaScript generates this parameter. #### WT.vt_f_a `WT.vt_f_a=1` SDC generates this parameter to track new visitors for an account. This parameter is generated and set to 1 for the first hit from a new visitor for a given account. This parameter is set to 2 if the visitor’s browser does not accept cookies. The First-Party Cookie JavaScript generates this parameter. This parameter is used in conjunction with Account Rollup Profiles. #### WT.vt_sid `WT.vt_sid=identifier` SDC generates this parameter to identify visitor sessions for Visitor Data Mart. This parameter is generated on every hit to identify the visitor session. This identifier is formed by concatenating two pieces of data: - *Identifier*: The value of `WT.co_f`. If `WT.co_f` is not present on the incoming hit, SDC generates this value. This is the unique identifier that is generated at the time of a new visit. It is 32-character hexadecimal number (0-9, a-f). - *Timestamp*: The time when the session began. This is the number of milliseconds since January 1, 1970. Example: `WT.vt_sid=10.61.19.29-3899933120.29768655.1141069` Note The First Party Cookie Javascript no longer emits `WT.vt_sid`. Rather, it now emits the two components (Identifier and timestamp) as separate parameters. See `WT.vtid` and `WT.vtvs` for more information. #### WT.vtid `WT.vtid=identifier` This parameter is used to identify visitors for Visitor Data Mart. By default, this identifier is provided by Webtrends Data Collection Servers using an in-line JavaScript request for `wtid.js` at the time of a new visit. Alternatively, this parameter value can come from a custom query parameter or customer cookie. Identifier: Any alphanumeric string that uniquely identifies a visitor. By default this value is the same as the `WT.co_f` parameter. #### WT.vtvs `WT.vtvs=timestamp` The JavaScript tag generates this parameter to identify visitor sessions for Webtrends Visitor Data Mart. This parameter is generated on every hit to identify the visitor session. *Timestamp*: The time when the session began. This is the number of milliseconds since January 1, 1970.