Sheet cut (cartography)
The sheet cut (also called map cut ) is the systematic subdivision of a map series into several smaller, more manageable partial maps according to a fixed scheme.
The cut of a map series can vary depending on the country, scale, cartography publisher and application. The distance of 1 ° geographical latitude corresponds to 111.3 km in Europe - in the USA ~ 100 m less, 1 ° geographical longitude corresponds to 111.2 km × cosine of the latitude - in Central Europe it is ~ 75 km. The aspect ratio of official maps for portrait × landscape in km² usually corresponds to about 1: 1.3 to 1: 1.4.
Official topographic maps usually have a paper format of 1: 50,000 and 1: 200,000 - portrait format in Austria, landscape format in Switzerland, depending on the type of paper, in Germany both - around 50 cm × 70 cm. The map image is ~ 10 cm smaller (edge and legend can be written on).
At 1: 100,000 there are formats from 40 to 80 cm wide. Official overview maps 1: 500,000 have a size of 50 cm × 70 cm and more. Nautical charts with 1: 100,000 to 500,000 are mostly in portrait format, as the meridians are closer together than the parallels.
The International World Map IWK 1: 1,000,000 has a 4 ° sheet cut and is 444 mm high without a map border, less across the board depending on the geographical latitude. The ICAO card has about two to three times the area. TPC have an area of around 600 km × 450 km. In Europe , 1 ° latitude corresponds to 111.3 km, in the USA ~ 100 m less, 1 ° geographical longitude 111.2 × cosine of latitude in Central Europe corresponds to ~ 75 km. Each degree of longitude or latitude is divided into 60 ' arc minutes . The aspect ratio of official maps is usually around 1: 1.3 to 1: 1.4 (similar to the 1: 1.4142 of the A4 format).
In official cartography in the national survey , the sheet section is based on the grid lines of geodetic or geographical coordinates . Because these coordinate lines converge towards the North Pole, the section of the sheet therefore usually deviates slightly from the rectangular shape.
In the case of publishing house cartography , the area to be represented is usually subdivided according to market economy criteria, ie with map sections according to the needs of tourism or mountain climbers . These sheet cuts are independent of any right-angled delimitations and are based on the format of the publication.
As in a puzzle, the partial maps can be laid together on the map cutting lines to form a larger map. In the case of small-scale maps, however, noticeable gaps always occur at the corners and edges because of the inevitable map distortion .
The topographic map 1: 25,000 (TK25) contains an extensive and detailed landscape representation and a large number of individual objects, such as buildings, bodies of water, sights and traffic routes. In addition, contour lines, embankment representations and height points show an exact image of the relief. The state of Lower Saxony is covered with 465 map sheets. One sheet of the TK25 covers an area of approximately 11 km × 11 km. The map is 0 ° 6 'high and 0 ° 10' wide, 1 cm in the map corresponds to 250 m in nature.
The topographic map 1: 50,000 (TK50) is slightly generalized for the landscape representation. The smaller scale enables the representation of a larger area and gives a good overview. The terrain forms are represented by contour lines, embankment representations and elevation points. The state of Lower Saxony is covered with 132 sheets and covers an area of approximately 22 km × 22 km. One sheet of the topographic map 1: 50,000 encloses the area of four sheets of the TK25, so is a total of 0 ° 12 'high and 0 ° 20' wide. 1 cm in the map corresponds to 500 m in nature.
The topographic map 1: 100,000 (TK100) enables the combined mapping of an entire region, gives a characteristic overview and, compared to the TK50, mainly shows a generalization in the representation of the vegetation. The height relationships are represented by contour lines, slope representations and height points. The state of Lower Saxony is covered by 40 map sheets and covers an area of approximately 45 km × 45 km. One sheet of the topographic map 1: 100,000 encloses the area of four sheets of the TK50, so is a total of 0 ° 24 'high and 0 ° 40' wide. 1 cm on the map corresponds to 1 km in nature.
scale 1: 5,000.
The individual map sheets of the German basic map have an extension of 40 cm × 40 cm, which is 2 km × 2 km.
Scales 1: 25,000 to 1: 200,000
Official maps are degree division maps in true-angle illustration according to Gauß-Krüger with 3 ° wide meridian strips according to Greenwich.
- 1: 25,000 - 10 minutes of length and 6 minutes of latitude equals 12.6 km to 10.6 km × 11.1 km
- 1: 50,000 - 20 minutes of length and 12 minutes of latitude equals 25.2 km to 21.2 km × 22.2 km
- 1: 100,000 - 40 minutes of length and 24 minutes of latitude equals 50.4 km to 42.4 km × 44.4 km
- 1: 200,000 - 80 minutes of longitude (1 ° 20 ') and 48 minutes of latitude equals 108.8 km to 84.8 km × 88.8 km
Due to the projection, a minute of length has a different extent in the south of the Federal Republic compared to one in the north. The map extent on a map scale of 1: 25,000 with 10 minutes of length in the southernmost map sheet 8727 Biberkopf is approx. 12.6 km, on the northernmost map sheet 0916 List (Sylt) only about 10.6 km. The extension of the 6 minutes of latitude corresponds to 11.1 km in nature. The approximate kilometer indication of the scale 1: 25,000 increases with each smaller one.
Electronic maps can be cut as desired, for example to download map sections for navigation devices. A regular sheet section is used to represent areas; for example, to depict rivers, railway lines or hiking trails, an irregular sheet section is useful. A country is shown on a map either as a rectangle with corresponding additional surrounding parts of the neighboring countries, or as a composition of individual small tiles that depict the country within the national border following this.
For example North Rhine-Westphalia
- German basic map 1: 5000 (DGK5) - smallest delivery unit: grid tiles with a side length of 2 km (4 km²)
- digital topographic map 1: 10,000 (DTK10) - smallest delivery unit: grid tiles with a side length of 2 km (4 km²)
- digital topographic map 1: 25,000 (DTK25) - standard sheet section: degree division map with 0 ° 10 'geographical longitude and 0 ° 6' geographical latitude, 1 map sheet depicts a landscape area of an average of 129 km² ≈ 20 dm² map image.
- digital topographic map 1: 50,000 (DTK50) - standard sheet section: degree division map with 0 ° 20 'geographical longitude and 0 ° 12' geographical latitude, 1 map sheet depicts a landscape area of an average of 516 km² ≈ 20 dm² map image.
- digital topographic map 1: 100,000 (TK100) - standard sheet section: degree division map with 0 ° 40 'geographical longitude and 0 ° 24' geographical latitude, 1 map sheet shows a landscape area of an average of 2,090 km² ≈ 20 dm² map image.
- digital overview map of NRW 1: 250,000 (NRW250) - shows the total area of about 34,000 km² of North Rhine-Westphalia on a map sheet.
- G. Hake, D. Grünreich, L. Meng: Cartography. de Gruyter, 2002