National technical regulations on national topographic maps at scales 1:2,000, 1:5,000 in Vietnam

National technical regulations on national topographic maps at scales 1:2,000, 1:5,000 in Vietnam (Internet image)

National technical regulations on national topographic maps at scales 1:2,000, 1:5,000 in Vietnam

Circular 03/2023/TT-BTNMT on National technical regulations on national topographic maps at Scales 1:2,000, 1:5,000 issued by the Minister of Natural Resources and Environment on June 27, 2023, and taking effect on December 29, 2023.

This national technical regulation provides technical regulations on the content, symbols, and metadata of national topographic maps at scales of 1:2,000 and 1:5,000.

This technical regulation applies to management agencies, organizations, and individuals related to the establishment, storage, management, provision, and use of national topographic maps at scales of 1:2,000 and 1:5,000.

In this technical regulation, the following terms are understood as follows:

National topographic map at scales 1:2,000, 1:5,000 is a topographic map of the mainland, islands, archipelagos, and seabeds built in the national coordinate system and national elevation system for uniform use throughout the country.

A scale symbol is a symbol whose size is proportional to the actual size of the feature.

A semi-proportional symbol is a symbol whose one dimension is proportional to the actual size of the feature, with the other dimension representing the convention.

A non-proportional symbol is a symbol with a geometric shape that represents a geographical object and a conventional size, not according to the actual size of the geographical object.

Units of measurement values shown on the map: altitude, depth, length, width, height ratio, and depth ratio in meters (m); Bridge and ferry tonnage is calculated in tons; Voltage in Kilovolts (kV), Volts (V).

National coordinate point is a national measurement point with coordinate values established according to national standards, technical regulations, and technical regulations.

National elevation point is a national measurement point whose elevation value is established according to national standards, technical regulations, and technical regulations.

National coordinate and elevation points are national measurement points with coordinate values and elevation values established according to national standards, technical regulations, and technical regulations.

National gravity point is a national measurement point whose gravitational force acceleration value is established according to national standards, technical regulations.

GeoTIFF is a digital image file with the extension *.tif associated with the coordinates of geographical objects in a specified coordinate system.

GeoPDF is a data file with the extension *.pdf associated with the coordinates of geographical objects in a specified coordinate system. GeoPDF files contain spatial data and properties of geographic features.

Accuracy of the national topographic map at scales 1:2,000, 1:5,000

- The square error in the plane of geographical objects represented on the national topographic map according to the established map scale must not exceed the following values:

+ 0.5 mm on the map for plains, hills, and low mountains;

+ 0.7 mm on the map for high mountains and hidden areas.

- The mean square error in the elevation of geographical objects represented on the national topographic map must not exceed the values specified in Table 1 below:

Table 1 - Regulation of mean square error on the altitude of geographical objects

For hidden and especially difficult areas, the above errors are allowed to increase by 1.5 times.

- When checking, the limit error in the plane and height of geographical features is not allowed to exceed 2.5 times the square error. The maximum error does not exceed the limit error. The number of cases with errors greater than 2.0 times the mean square error does not exceed 5% of the total number of test cases. In all cases, the errors are not systematic.

Duong Chau Thanh

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