Search results
Results From The WOW.Com Content Network
When performing a resection (free stationing) with the total station, bearings and distances are measured to at least two known points of a control network. With use of a handheld computer , recorded data can be related to local polar coordinates , defined by the horizontal circle of the total station.
A visual fix can be made by using any sighting device with a bearing indicator. Two or more objects of known position are sighted, and the bearings recorded. Bearing lines are then plotted on a chart through the locations of the sighted items. The intersection of these lines is the current position of the vessel.
An absolute bearing is measured with a bearing compass. The measurement of absolute bearings of fixed landmarks and other navigation aids is useful for the navigator because this information can be used on the nautical chart together with simple geometrical techniques to aid in determining the position of the vessel.
Public Land Survey System in Google Earth - a free Google Earth implementation of the National Integrated Land System (NILS) GeoCommunicator map service; Sample of PLSS in ESRI ArcGIS - Alabama PLSS; Convert PLSS to latitude and longitude; Tools and APIs to convert PLSS to geographic locations and display it on a map
The projection found on these maps, dating to 1511, was stated by John Snyder in 1987 to be the same projection as Mercator's. [6] However, given the geometry of a sundial, these maps may well have been based on the similar central cylindrical projection, a limiting case of the gnomonic projection, which is the basis for a sundial. Snyder ...
These instruments are used primarily to measure the elevation or altitude of a celestial object: Back staff, the best known of which is the Davis' quadrant. It could measure the altitude of the Sun without having the navigator directly observe the Sun. Cross staff, an older instrument long out of use.
The resulting bearing indicated is the magnetic bearing to the target. Again, if one is using "true" or map bearings, and the compass does not have preset, pre-adjusted declination, one must additionally add or subtract magnetic declination to convert the magnetic bearing into a true bearing. The exact value of the magnetic declination is place ...
Measure Map Pro format (MMP) is an XML notation to store GIS information in two-dimensional or three-dimensional maps. It was created by Blue Blink One to store information about Polygons, Polylines and Spots including georeferenced labelling, grids and comments.