Technical regulations on national topographic maps when drawing maps of Vietnam applied from December 30, 2022?
Regulations on size in technical regulations of national topographic maps (Maps of Vietnam) ?
According to Section I of Circular 06/2022/TT-BTNMT on national technical regulations on national topographic maps of Vietnam as follows:
- Scope
+ This national technical regulation prescribes the content and symbols of national topographic maps at scale 1:50,000, 1:10,000 compiled from the national geographic database at scale 1. :50,000, 1:100.000.
- Subjects of application
+ This technical regulation applies to management agencies, organizations and individuals involved in the establishment, storage, management, supply and use of national topographic maps at the scale of 1:50,000 , 1:100,000.
- In this technical regulation, the following terms are construed as follows:
+ National topographic map at scale 1:50,000, 1:100,000 is a topographic map on the mainland, islands, archipelago and seabed topographic map built in the national coordinate system and the 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.
+ The half-scale symbol is a symbol whose size in one dimension is proportional to the actual size of the feature, the other dimension represents the convention.
+ Non-scale symbol is a symbol with a pictogram for a feature and a conventional size, not according to the actual size of the feature.
+ Units of measurement values shown on the map: altitude, depth, length, width, height, depth in meters; tonnage of bridges and ferries in tons.
+ National coordinate point is a national measurement point whose coordinate value is established according to national standards, technical regulations and technical regulations.
+ National elevation point is a national measurement point whose altitude value is established according to national standards, technical regulations and technical regulations.
+ National coordinate and altitude point is a national measurement point whose coordinate value and altitude value are established according to national standards, technical regulations and technical regulations.
+ National gravity point is a national measurement point with the value of gravitational acceleration established according to national standards, technical regulations and technical regulations.
+ GeoTIFF is an image format associated with geographic coordinates
Technical regulations on national topographic maps when drawing maps of Vietnam applied from December 30, 2022? (Image from the internet)
What is the regulation on the accuracy of the national topographic map (Maps of Vietnam)?
According to subsection 4, Section I, Circular 06/2022/TT-BTNMT on national technical regulations on national topographic maps as follows:
- Accuracy of national topographic maps at scale 1:50,000, 1:100,000
+ Accuracy of topographic maps on mainland, island, archipelago
+. The mean square error on the plane of the geographical features shown 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 of elevation of geographical features shown on the national topographic map must not exceed 1/3 of the equidistant elevation of the basic contour line. For hidden and particularly difficult areas, the allowed tolerances are increased to 1.5 times.
- Accuracy of seabed topographic map
+ The square error on the plane of the geographical features shown on the seabed topographic map according to the established map scale must not exceed the following values:
++ 0.4 mm on the map for depth notes, bottom notches;
+ 0.5 mm on the map for floating features of fixed nature on the sea surface; for floating features that are mobile on the sea surface, such as buoys and channel lights, the moving range of that feature shall be added;
++ 1.0 mm on the map for submerged features.
+ The square error of the depth of the depth measurement point determined by the formula must not exceed the following values:
++ ± 0.3 m when the depth is up to 30 m;
++ 1.5% depth when the depth is from 30 m to 100 m;
++ 2.5% depth when the depth is more than 100 m.
- Where: is the difference in depth between the depth measuring line and the test measuring line at the intersection of the two measuring lines; the depth at this intersection is interpolated from the 2 nearest depth measurement points before and after the intersection on each measuring line; n is the number of intersections.
+ The mean square error of the depth of the seabed topography determined by the formula must not exceed the following values:
++ 2/3 of the average height of the basic depth contour for terrain with slope less than 6°;
++ Equal to the average elevation of the basic depth contour for terrain with slopes greater than 6°.
- In which: is the difference in depth between the test measuring point and the depth point at the same location interpolated from 2 adjacent contour lines on the topographic map of the seabed; n is the number of test points.
+ The margin of error on the seabed topography on the seabed topographic map at scale 1:50,000, 1:100,000 must not exceed 1.5 times the errors specified at point 4.2 of this Part.
++ When testing, the limit error on the plane and the height of the features is not allowed to exceed 2.5 times the mean square error. The number of cases with errors greater than 2.0 times the mean squared error does not exceed 5% of the total number of test cases. In no case should the errors be systematic.
What are the technical regulations in the national topographic map product format (Vietnam Map)?
According to subsection 5, Section I of Circular 06/2022/TT-BTNMT on national technical regulations on national topographic maps as follows:
- Product format of national topographic maps at scale 1:50,000, 1:100,000
+ National topographical map at scale 1:50,000, 1:100,000 including digital form and printed form on paper.
+ National topographic map in digital format in GeoTIFF format with a resolution of 300 dpi or more and GeoPDF format. Each piece of a digital national topographic map has an accompanying metadata file.
Circular 06/2022/TT-BTNMT takes effect from December 30, 2022.
Lê Nguyễn Cẩm Nhung
