![]() ![]() The thing is, different ellipsoids, and therefore different datums, are often used depending upon where in the world you are. These definitions are referred to as a Datum. The Latitude and Longitude coordinate system can describe any point on earth, however, it can only do that if we have first defined the details of the earth such as the origins of the Latitude and Longitude system and the size and shape of the ellipsoid to be used. The earth is ellipsoidal, albeit with a few lumps and bumps. If you took at an inflated beach ball, placed your foot on it and gently pressed, you would have a squashed sphere, referred to as an ellipsoid. Ordnance Survey provides detailed documentation in relation to coordinate systems used in the UK. One thing I should mention is that this article is a greatly simplified discussion of a complex topic. Net 4.5+, Windows Phone 8+, Xamarin.IOS/Android, Windows 8 Store Apps and so on. GeoUK was built as a Portable Class Library project (Profile 78) and as such can be added to Visual Studio or Xamarin and runs against. ![]() The freely available GeoUK NuGet package is used for these examples. The article will walk through some C# examples, including how to convert from GPS coordinates to British National Grid and back again. More detailed indexes are provided by the 1:63,360 sheets, on which each 10-kilometre grid line is emphasized, and by the 1:625,000 maps which are also gridded at 10-kilometre intervals.This article aims to demystify the concepts of transforming from one coordinate system to another. The number of each 1:10,560 sheet is linked to the number of its 'parent' 1:25,000 sheet: for example, if the 1:25,000 sheet number were TQ 47, the 1:10,560 sheet relating to its north-east quadrant would be TQ 47 NE. Each sheet of the National Grid 1:10,560 map, with sides representing five kilometres, depicts a quarter of the area shown on a 1:25,000 sheet. The numbering of National Grid maps derives from the numbering of sheets of the1:25,000 map, each of which is based on a ten-kilometre square. A note on the relationship between true, magnetic, and grid north appears in the south margin of the sheet, together with an explanation of how to give a National Grid reference correct to 100 metres, two panels of conventional signs, an index diagram to adjoining sheets, a 'survey diagram' where appropriate, giving the dates of survey of component larger scale sheets and, beneath, revision notes on other information on the map. Outer borders are graduated in scales of feet (west), yards (south), furlongs (east), and links and chains (north). All sheets also show latitude and longitude in association with the inner border abbreviated values are given at 1-minute intervals and full values, in degrees and minutes, accompanying the 1-minute interval nearest to the sheet corners. An inner border is divided at 100-kilometre intervals. Full grid values are given at the corners of each sheet, and the intervening values in kilometres, by the last two figures of the kilometre values from 00 to 99 inclusive. National Grid lines are shown at one-kilometre intervals. However, some sheets have an extended layout, especially where, as in coastal areas, this avoided the creation of sheets with large blank areas. It was originally intended that each sheet would represent a quadrant of a 10-kilometre square of the National Grid and so depict an area 5 x 5 kilometres. This series, however, contains a large number of Provisional Edition sheets: these are indicated in the catalogue. On publication of the Regular Series sheets, the corresponding Provisional Edition sheets were withdrawn. The Provisional Edition was not intended to be a definitive publication. As far as possible, the Provisional Edition incorporated revision undertaken between 19 at the 1:10,560 scale for the preparation of the Seventh Series one-inch (1:63,360) map. The sheets were produced by fitting the material of the County Series sheets, together with revision data, into the framework of the National Grid, with a minimum amount of redrawing. This map was designed to provide, as quickly as possible, an up-to-date map from the best available information. Ordnance Survey of Great Britain: Six-Inch Maps: National Gridīetween 19, a new edition of the six-inch (1:10,560) map began to be issued 'on National Sheet Lines'.Ī Provisional Edition of the 1:10,560 map on National Grid sheetlines was introduced in 1953. ![]()
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