Assumed Meridian
Assumed Meridian - Related Videos
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Meridians
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In surveying, meridians are vital reference lines to measure directions and establish accurate land orientations. Meridians run from the north to the south poles, providing a stable framework for angular measurements and mapping. Meridians are fundamental in survey design, with the primary types being astronomic, magnetic, and assumed meridians. Each type offers distinct benefits and limitations, selected based on the project's scale and precision needs.The astronomic meridian is aligned with...
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Quality Assurance
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Quality assurance is the overarching term used to describe the activities employed to ensure the proper performance of a system. These activities can be classified into three categories: quality control, quality assessment, and internal corrective measures. Typically, these activities work cyclically: quality control is performed before and during the analysis, while quality assessment occurs during and after the investigation. Internal corrective measures are implemented based on the findings...
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This protocol presents a novel approach to alleviating the symptoms and improving the quality of life of patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) by employing moving cupping along meridians therapy to stimulate the first sideline of the bladder meridian.
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Construction of a Preclinical Multimodality Phantom Using Tissue-mimicking Materials for Quality Assurance in Tumor Size Measurement
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Cited by 1 •
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This paper describes in-house procedures of constructing a preclinical multimodality phantom made of tissue-mimicking (TM) materials for quality assurance (QA) of tumor size measurement in animal imaging modalities such as ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI).
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Troubleshooting and Quality Assurance in Hyperpolarized Xenon Magnetic Resonance Imaging: Tools for High-Quality Image Acquisition
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Here, we present a protocol for obtaining high-quality hyperpolarized xenon-129 magnetic resonance images, covering hardware, software, data acquisition, sequence selection, data management, k-space utilization, and noise analysis.
FAQs
The assigned bearing acts as the computational starting point for the survey. Once that value is fixed, each measured horizontal angle is referenced to the same line, so bearings for traverse lines, boundaries, and site features remain internally consistent. Changing the starting bearing would change the numerical bearings, but not the local angular relationships represented by the survey.
An Assumed Meridian is useful when the survey requires dependable local direction rather than a globally oriented bearing. Unlike a true meridian, it does not depend on astronomical observations, and unlike a magnetic meridian, it does not require magnetic instruments. Its limitation is that the resulting bearings are relative, so they cannot by themselves establish a universal geographic orientation.
Clockwise horizontal-angle measurement provides the link between the reference line and each surveyed direction. The surveyor observes the angle from the selected line, then uses the assigned reference bearing to determine the bearing of the target line or feature. This relationship supports directional computations for traverses, property boundaries, and site elements within the same local framework.
Using an Assumed Meridian begins with selecting a suitable reference line and assigning it a bearing, commonly 0° or another convenient value. The surveyor then measures horizontal angles clockwise from that line to relevant directions. Those observations are used to determine bearings for the traverse, boundaries, or site features included in the survey.
In construction layout, the method supplies a consistent directional framework for positioning site features without requiring a true or magnetic orientation. It also suits local engineering surveys, where the immediate relationships among lines matter more than their global direction. Preliminary route planning can similarly use relative bearings to organize alternatives before a connection to a broader reference system becomes necessary.
Relative bearings remain useful beyond the initial local survey because the assumed framework can later be related to a true or magnetic meridian when broader orientation is required. This preserves the value of the original measurements while allowing the work to connect with a globally or magnetically oriented system. The selected reference and its assigned bearing must remain documented.