National Geodetic Survey (NGS)
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US federal agency site providing the National Spatial Reference System: geodetic control datasheets, CORS GPS station data, OPUS positioning, and geoid models. Surveyors use it to tie field observations to official horizontal and vertical datums.
More resources on Surveying & Geomatics
qgis.org
QGIS.org is the official homepage for QGIS, the free open-source desktop GIS. It provides software downloads, comprehensive documentation, tutorials, a plugin repository, and community resources for learning and applying GIS and surveying/geomatics workflows.
nsps.us.com
Official site of the National Society of Professional Surveyors (NSPS), offering resources for surveying and geomatics professionals—education and training, certification and standards, publications, events, and industry news.
Elementary Surveying
A long-standing introductory textbook covering distance, angle, and elevation measurement, traversing, leveling, error theory, and topographic mapping. Readers finish able to run and adjust basic survey computations and interpret field notes and plats.
Surveying
A classic civil engineering text on plane surveying: measurement of distances and angles, leveling, traverse adjustment, curves, earthwork volumes, and photogrammetry. Covers the instrument procedures and computations used on route and construction projects.
GPS for Land Surveyors
Explains satellite positioning for survey work: signal structure, biases, differential and RTK techniques, static observation planning, and coordinate datums. After reading it you can design a GPS control survey and judge the accuracy of results.