![]() The following are three common means of representing latitude and longitude.Ĭlassic representation of latlong coordinates, pretty much understandable by everyone. Latitude and Longitude, being references on a sphere (not a proper sphere, but let’s keep this simple) are the offset in degrees from a common reference meridian and parallel. If precision ordnance guided by means of GPS is employed, we better make sure that the target location is instead very accurate. This is not always a priority: a waypoint in the F-14 flight plan can be slightly more to the North or the East than its precise original location with little negative effects. Latitude and Longitude can be represented in different ways and players should make sure that a common format is used. In DCS, the simplest and most common way to define them is by means of latlongs, short for Latitude and Longitude, as they are cross-faction (imperial vs metric, east vs west), cross-module and they should sound familiar already.īy using latitude and longitude, for example, a Ka-50 FAC/A can share the location of a target with an A-10C although they have very little in common (no datalink, different system of measurement, etc). The position of an object, a target or a waypoint on the planet can be represented in many ways. NATO MGRS), I may cover them in the future. For this reason more advanced means of representing positions are omitted in this article (e.g. The goal is introducing some fundamental topics in, hopefully, a simple and concise way. Print media usually conforms to a common standard such as that of the International Organization for Standardization (ISO) or North American paper size standards used by architects and civil engineers.This article is aimed mostly to new players. Usually a mismatch between drawing units and the assigned spatial reference, rather than drawing scale, is the root cause of scaling discrepancies encountered in ArcGIS when working with CAD data. It is independent of the actual CAD model data and generally has no effect on how the data is displayed in ArcGIS Desktop. Drawing scale and print mediaĭrawing scale is a display function performed in the drawing's page layout views. For example, the units in a drawing of the interior space of a building is likely to be in inches or millimeters, whereas a drawing of a survey plat or a landscape plan is likely to be in feet or meters. The decision usually rests on the level of detail the drawing is intended to capture. One drawing unit can represent any linear unit of measure such as inches, millimeters, meters, or feet. ![]() Linear units in a CAD file are not dependent on, nor are they defined by, the data's coordinate system-they are a simple matter of the author deciding what the drawing units represent before he or she begins creating the data.Īs a general rule, all CAD drawings (or models) are drawn at full scale (1:1). Typically, features are measured relative to other features using distances that have been measured at local ground elevations. ![]() The x-axis can be thought of as an easting direction and the y-axis as a northing direction, but they do not necessarily translate to grid directions in your spatial data.Īlthough it is possible to create CAD data that corresponds to the x,y coordinates of a projected grid zone, most CAD data is authored without this consideration. X-, y-, and z-coordinates are not inherently geographic locations instead they are locations relative to an arbitrary geometric origin (0,0,0). MicroStation and AutoCAD use 2D and 3D Cartesian coordinate systems that locate data at fixed coordinates. This topic explains CAD coordinate systems and why integrating CAD data with maps can sometimes be problematic. Consequently, CAD data is generally smaller in scale than GIS data but capable of high levels of detail. At this scale, design intent and geometric accuracy are the primary focuses of the analysis rather than actual geographic location. Conversely, a CAD system is used to model the actual objects at a scale that is relatively unaffected by the earth's surface. A GIS models the world and the objects on it at a regional or global scale. The issue of scale defines a fundamental difference between how GIS and CAD systems utilize coordinate systems.
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