Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena.
While the invention of the method is attributed to Aimé Laussedat, the term "photogrammetry" was coined by the German architect Albrecht Meydenbauer, which appeared in his 1867 article "Die Photometrographie."
Forest management is a branch of forestry concerned with overall administrative, legal, economic, and social aspects, as well as scientific and technical aspects, such as silviculture, forest protection, and regulation. This includes management for timber, aesthetics, recreation, urban values, water, wildlife, inland and nearshore fisheries, wood products, plant genetic resources, and other forest resource values. Management objectives can be for conservation, utilisation, or a mixture of the two. Techniques include timber extraction, planting and replanting of different species, building and maintenance of roads and pathways through forests, and preventing fire.
Many tools like remote sensing, geographic information systems (GIS), and photogrammetry have been developed to improve forest inventory and management planning. Scientific research plays a crucial role in helping forest management. For example, climate modeling, biodiversity research, carbon sequestration research, GIS applications, and long-term monitoring help assess and improve forest management, ensuring its effectiveness and success.
A "quadrangle" is a topographic map produced by the United States Geological Survey (USGS) covering the United States. The maps are usually named after local physiographic features. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas quad". A quadrangle is defined by north and south boundaries of constant latitude (which are not great circles so are curved), and by east and west boundaries of constant longitude.
From approximately 1947–1992, the USGS produced the 7.5 minute series, with each map covering an area one-quarter of the older 15-minute quad series, which it replaced. A 7.5 minute quadrangle map covers an area of 49 to 70 square miles (130 to 180 km). Both map series were produced via photogrammetric analysis of aerial photography using stereoplotters supplemented by field surveys. These maps employ the 1927 North American Datum (NAD27); conversion or a change in settings is necessary when using a GPS which by default employ the WGS84 geodetic datum. Beginning in 2009, the USGS made available digital versions of 7.5 minute quadrangle maps based on GIS data that use the NAD83 datum, which is typically within one meter of WGS84, or within the uncertainty of most GPS coordinate measurements. The USGS also produces quarter quadrangle (QQ) maps of areas 3.75 minutes square.