Circular No. 05/2012/TT-BTNMT stipulates technical procedures for updating national topographic maps at scales of 1:25,000 and 1:50,000 using satellite imagery.

CIRCULAR

Technical regulations for updating national topographic maps at scales of 1:25,000 and 1:50,000 using satellite imagery

and 1: 50,000 by satellite imagery

 

Pursuant to Decree No. 25/2008/NĐ-CP dated March 1, 2008 of the Government stipulating the functions, tasks, powers, and organizational structure of the Ministry of Natural Resources and Environment;

Pursuant to Decision No. 81/2010/QD-TTg dated December 13, 2010 of the Prime Minister on the receipt, storage, processing, exploitation, and use of national remote sensing data;

Considering the proposal of the Director of the Vietnam National Mapping Center, the Head of the Legal Department, and the Head of the Science and Technology Department;

The Minister of Natural Resources and Environment promulgates this Circular on technical regulations for updating national topographic maps at scales of 1:25,000 and 1:50,000 using satellite imagery.

PART I

GENERAL PROVISIONS

Article 1. Scope of Regulation

This Circular provides for technical regulations for updating national topographic maps at scales of 1:25,000 and 1:50,000 using satellite imagery.

Article 2. Applicability

This Circular applies to state management agencies for surveying and mapping, domestic organizations and individuals, and foreign organizations and individuals operating in the field of surveying and mapping in Vietnam.

Article 3. Explanation of Terms

In this Circular, the following terms shall be understood as follows:

1. Updating a topographic map is the process of recreating the content of the map to reflect current reality according to the technical standards of national topographic maps.

2. Satellite imagery is a type of remote sensing image recording the surface of the Earth using equipment placed on satellites.

3. Image pixel (Picture Element) is the smallest element of an image recorded on the sensor device of the receiving equipment.

4. Ground resolution (Ground Resolution) or ground sampling distance (Ground Sampling Distance) or pixel size (Pixel Size) is the size of one image pixel projected onto the ground.

5. Spatial resolution is the smallest size of an object or the minimum distance between two adjacent objects that can be distinguished on an image. This resolution depends on the size of the image pixel, image contrast, atmospheric conditions, and satellite orbit parameters.

6. Digitized line map is a document used to record the results of tracing from the original map used for updating.

7. Change record is a document recording changes in map content elements that no longer exist or have changed in shape (part lost). A change record is established on a printed paper map derived from the original map to be updated.

8. Digital elevation model (DEM) is a numerical representation of continuous height variations of the terrain surface. The digital elevation model is used in orthorectification to eliminate geometric distortions caused by terrain elevation differences.

9. Orthorectification of satellite imagery is the process of correcting geometric distortions of the image caused by the imaging process and the influence of terrain elevation differences, while converting the coordinates of image points from spatial projection to vertical projection.

10. Enhancing satellite image quality involves radiometric correction (gray level processing for full-color images, spectral processing for multispectral images) to improve the information content of the image.

11. Resampling satellite imagery is the process of converting pixels from the original image (unrectified image) to pixels of the orthorectified image or resizing the pixel size of the image.

12. Tracing satellite imagery for updating maps is the process of identifying, interpreting, verifying, and recording changes in map content elements based on satellite imagery.

Article 4. Periodic Updating

1. From 4 to 8 years for maps at a scale of 1:25,000.

2. From 5 to 10 years for maps at a scale of 1:50,000.

Article 5. Updating Based on the Degree of Content Change

1. Topographic maps must be updated when the content changes from 20% to 40% and these changes significantly affect the use of the map.

The method for determining the degree of change in map content is specified in Appendix 1 attached to this Circular.

2. Topographic maps cannot be updated but must be newly established when:

a) The control basis for the horizontal plane and elevation of the map does not meet the accuracy requirements;

b) The quality of the original map established previously does not meet the requirements of national topographic maps;

c) The content elements of the map have changed more than 40%;

d) The content elements of the map have changed less than 40%, but compared to establishing a new map, updating will not be economically viable and will not ensure technical requirements.

Article 6. Maps After Updating

1. They must have mathematical foundations, accuracy, content, symbols, and presentation formats according to the regulations of national topographic maps.

2. Ensure that the content of geographic features on the map is consistent with the actual conditions at the time of updating, including: water systems and related objects, terrain, roads and related objects, population and cultural-economic-social objects, vegetation, national borders and administrative boundaries. For terrain elements, only micro-topography adjustments are made in relation to changed geographic features.

3. Data must be standardized, content layers named, object codes and source files containing standards according to the Technical Regulations for Digitizing Topographic Maps at scales of 1:10,000, 1:25,000, 1:50,000, and 1:100,000, issued together with Decision No. 70/2000/QĐ-ĐC dated February 25, 2000, by the Director General of the National Land Administration.

Article 7. Original Maps for Updating

Original maps for updating must be national topographic maps or topographic maps established according to technical criteria equivalent to those of national topographic maps, at scales of 1:25,000 or 1:50,000.

Original digital maps for updating must be established or updated at the most recent time.

Article 8. Satellite Images for Updating

1. Images used for updating must have a resolution of 0.1 mm per map scale; in special cases, images used may have a maximum resolution of 0.2 mm per map scale.

2. Images used for updating must be acquired at the latest time, no more than one year before the time of updating. If such image data is unavailable, images acquired two to three years prior to the time of updating may be used, but an assessment of the degree of change in the field relative to the images must be conducted to determine the usability of the images and find technical solutions to address the limitations of the images.

3. Images used for updating must have uniform contrast and the ability to clearly distinguish objects on the images.

Article 9. Recording History and Inspection - Acceptance of Updated Products

1. Each piece of an updated map must have a map history record attached.

2. Inspection - acceptance of updated products shall be carried out according to Circular No. 02/2007/TT-BTNMT dated February 12, 2007, of the Minister of Natural Resources and Environment guiding inspection, review, and acceptance of surveying and mapping works and products. Products to be inspected and accepted include:

a) Results of satellite image control measurements;

b) Digital satellite image plans;

c) Results of satellite image tracing, supplementary measurement results (if any);

d) Original maps for updating.

Chapter II

PREPARATION WORK

Article 10. Collection of data

The data to be collected for the revision of topographic maps includes:

1. Data from the base map for revision.

2. Satellite image data for revision purposes.

3. Supplementary data and supporting data in the form of maps, GIS databases, textual documents, statistical data, and tables of results from geodetic points and basic cadastral points.

4. Technical design, technical summary reports, map history, and other related technical documents concerning the map to be revised.

Article 11. Evaluation of the accuracy of the base map for revision

1. Assessment methods

a) Comparing control points on the horizontal plane and height of the map with technical standards stipulated in current regulations through analyzing technical summary reports, coordinate and height tables of geodetic points, and map history;

b) Field verification measurements;

c) Verification on larger scale topographic maps.

For base maps established using aerial photography methods or compiled from larger scale topographic maps, when evaluating accuracy, it is not necessary to check all sections within the revision area comprehensively, but only selective checks are required. If errors exceeding the allowable limits are found, then each section of the map in the entire revision area must be checked individually.

2. Allowable differences

a) The average difference in position of clear objects on the map to be revised compared to the verification results shall not exceed 0.6 mm in plains and hills, and 0.8 mm in mountains and high mountains according to the map scale;

b) The average difference in height of marked points on the map to be revised shall not exceed half the mean height difference between contour lines;

c) The limit difference in horizontal position and height shall not exceed twice the value of the aforementioned average differences, and the number of such points shall not exceed 10% of the total number of verification points.

3. Assessment of the completeness and correctness of the representation and the degree of change of the content elements of the map to be revised is conducted by comparing and contrasting the map with satellite images used for revision or with newly established larger scale topographic maps. Additionally, this assessment can be made directly during field surveys.

The evaluation results must provide conclusions on the usability of the map as a base for revision and the extent of revision needed.

Article 12. Study of Geographic Characteristics of the Revision Area

This involves analyzing and assessing natural conditions and socio-economic factors affecting the revision work of the map. This work is carried out indoors based on descriptive materials, maps, and satellite images. It is also supplemented through fieldwork.

The research results must provide the following conclusions:

1. Distribution characteristics and geographic features of content objects affecting the criteria and methods of representation on the map.

2. Nature and degree of change of content objects on the map affecting the extent of revision and revision plans.

3. Specific natural and socio-economic conditions affecting the implementation of map revision projects.

Article 13. Field Survey

Field surveys are conducted along routes and at points. Prior to conducting the survey, a survey plan must be prepared, marking the positions of points and routes to be surveyed and outlining the implementation plan. The objectives of the field survey are:

1. To supplement the indoor study of geographic characteristics of the revision area.

2. To supplement the indoor assessment of the map to be revised.

3. To conduct surveys and establish samples for satellite image mapping.

4. To collect local data.

5. To survey the current status of national coordinate and elevation control points used for image control measurements.

Article 14. Preparation of Technical Design - Budget Estimate

1. The Technical Design - Budget Estimate shall be prepared based on the evaluation of documents, research on the geographical characteristics of the area to be updated, and field surveys.

2. The Technical Design - Budget Estimate may only be used for construction, product inspection - acceptance, and final settlement of the project after being approved by the competent authority.

3. The contents of the Technical Design - Budget Estimate are specified in Appendix 3 of the Management Regulations for Programs, Projects, and Specialized Tasks, issued together with Decision No. 1029/QĐ-BTNMT dated May 31, 2011, of the Minister of Natural Resources and Environment.

4. Depending on specific requirements, detailed technical guidelines must be established for certain critical stages, such as: guidelines for using materials, guidelines for image adjustment, guidelines for supplementary mapping, and guidelines for map editing.

The process diagram for updating topographic maps using satellite images is stipulated in Appendix 2 attached to this Circular.

Chapter III

CONTROL OF SATELLITE IMAGES

Article 15. Control Point Design for Satellite Images

1. Control points for satellite images must be selected at easily identifiable locations and must have clear images on the photos. Specifically, as follows:

a) At intersections between geographic features or edges of linear geographic features (roads, levees, dams, canals, streams) with angles of intersection ranging from 30° to 150°;

b) At distinctive points of independent objects (bridges, culverts, corners of buildings);

c) In cases where the aforementioned positions cannot be selected, control points may be chosen at distinctive features along small river or stream bends with a curvature diameter less than 0.3 mm according to the scale of the photo;

d) Control points for satellite images should not be selected at locations with sudden changes in elevation (in areas with mountain passes, slopes, cliffs).

2. Number and arrangement of control points for satellite images.

a) Control points for satellite images must cover all scenes within the area to be updated. There must be 12-18 control points evenly distributed in each satellite scene. If there are insufficient control points in one scene, that scene must be linked to adjacent scenes to supplement control points. Within the linked scenes, there must be at least two control points located in the overlapping area between two scenes;

b) Each scene must have at least two check points, arranged between control points. Check points must be determined with accuracy equivalent to control points;

The design layout diagram for control points is specified in Appendix 3 attached to this Circular.

Article 16. Field Measurement of Satellite Image Control Points

1. Satellite Image Control Points

a) Satellite image control points must be points with accurately determined coordinates and elevations, ensuring they can be identified with precision up to 0.5 pixels on satellite images and without any positional changes during construction. Satellite image control points must be chosen in convenient locations for measurement and must be compatible with measuring equipment;

b) Satellite image control points must be marked with wooden stakes or painted marks on-site, ensuring their preservation throughout the construction and inspection - acceptance period;

c) Satellite image control points and check points must be punched onto the control image at the actual site, with punch hole diameters not exceeding 0.15 mm on the image. National coordinate and elevation points used as bases for connecting satellite image control points must also be punched onto the image like satellite image control points;

d) All points punched onto the field control image must be adjusted on both sides of the image. On the front side of the image, points are circled and named with non-fading ink (red for planimetric control points, blue for elevation control points). On the back side of the image, a sketch noting the points is drawn in black pencil, enlarged 2 to 4 times. The lines and background of the sketch must resemble those on the image. In the point notes, the point number and detailed location description must be clearly recorded.

2. Connection Measurement of Satellite Image Control Points

a) Satellite image control points must be connected to national coordinate and elevation points;

b) Coordinates and elevations of satellite image control points are determined using GPS measurement methods or other geodetic measurement methods;

c) The control network for satellite image control points must be calculated and adjusted in the VN 2000 National Coordinate System and the National Elevation System of Vietnam;

d) A connection measurement layout diagram is prepared after completing the connection measurements of coordinates and elevations. The diagram shows the scenes measured, scene numbers, state geodetic base points used for connections, control points, check points, and connection directions. Additionally, the main hydrographic system is also shown on the diagram.

3. Positioning errors for planimetric and elevation control points for satellite image control points are regulated in Points 2.4.3 and 2.4.4 of the Technical Regulations for Establishing Topographic Maps at scales of 1:10,000, 1:25,000, and 1:50,000 Using Digital Image Technology, issued together with Decision No. 15/2005/QĐ-BTNMT dated December 13, 2005, of the Minister of Natural Resources and Environment.

Article 17. Determining Control Points on Photographs on Maps

1. The map used to determine control points on photographs must be a digital national topographic map at a larger scale than the photograph plan to be established.

2. The objects selected as control points on photographs must have clear images both on the photographs and on the maps, not distorted due to the generalization process of the map or displaced due to large symbol sizes, and must also have the ability to interpolate heights. The recognition and marking error of the selected control points on the map must not exceed ± 0.1 mm.

3. The coordinates of the control points on photographs are determined on the digital map using the "information extraction" tool of image processing software, digital map software, or GIS.

4. The images, positions, and descriptions of the control points on photographs are stored in a data file (hereinafter referred to as file) of the selected control points on the map.

Chapter IV

ESTABLISHING PHOTOGRAPH PLANS FROM SATELLITE IMAGES

Article 18. Inputting Satellite Image Data

Digital satellite image data with a format compatible with the technical features of the image processing system is directly inputted. If it is incompatible, intermediary software must be used to convert the data format before inputting into the image processing system.

Article 19. Transferring and Assigning Coordinates and Elevations of Control Points on Digital Images

1. Control points on photographs are transferred to digital images with an accuracy ≤ 0.5 pixels.

2. Control points must be assigned coordinates and heights based on the results of field control measurements or determined from larger-scale topographic maps.

3. The images, positions, and descriptions of the control points must be stored in the database of the image processing system.

Article 20. Rectifying Satellite Images

1. Satellite images are rectified scene by scene. The size of the rectified image pixel must not exceed 0.2 mm on the photograph plan.

The gray level value of each pixel is interpolated using the nearest neighbor method, bilinear method, or cubic interpolation method.

2. Satellite image modeling is performed using physical models when all photography parameters and suitable software are available, or using other mathematical models (rational function model, polynomial model, affine model, direct linear transformation model, grid projection transformation model) when full photography parameters and suitable software are not available.

3. A digital elevation model is used to rectify satellite images when the positional displacement of image points caused by terrain height differences is ≥ 0.3 mm according to the scale of the photograph plan. Otherwise, the average plane of the entire area is used for rectification.

The permissible error of the digital elevation model used to rectify satellite images is specified in Table 1 and Table 2 of Appendix 4 issued together with this Circular.

4. The average positional difference between identical objects on the rectified photograph plan and the required topographic map must not exceed 0.4 mm for distinct objects and must not exceed 0.6 mm for indistinct objects.

Article 21. Joining Images and Cutting Pieces of Satellite Photograph Plans

1. Image joining is carried out when the photograph plan to be established lies across multiple satellite image scenes.

a) The seam of the joined images must not pass through the control points used for rectification and along linear objects. The angle between the seam and linear objects must be within the range from 30° to 150°.^° up to 150^°;

b) The image matching error when joining objects on rectified images does not exceed 0.6 mm in plain areas and does not exceed 1.0 mm in mountainous regions;

b) The image joining error at the boundary of objects on the rectified image must not exceed 0.6 mm in flat areas and must not exceed 1.0 mm in mountainous areas;

c) Within a 60-pixel buffer zone around the seam, color balancing must be performed to ensure that the colors of the two joined images are uniform.

Article 22. Enhancing Image Quality

1. Image quality enhancement is carried out at the display level on the screen, then saved in digital image file format.

The process of enhancing image quality is conducted for each spectral channel using linear stretching methods, interactive adjustment methods, or other methods.

2. Enhancement of multi-spectral image quality through color combination solutions is implemented according to natural color combination schemes or artificial color combination schemes, depending on the requirements set forth.

3. Image quality enhancement through the combination of multi-spectral images with full-color images must meet the following requirements:

a) The images used must not be taken too far apart in time;

b) The disparity between corresponding objects on different images must not exceed 0.5 pixels of the lower resolution image;

c) The resolutions of the images must not differ more than fourfold.

4. Digital image maps after image quality enhancement must ensure clarity, uniform contrast in tonality, no color bias, and consistent coloration across all image stitching areas. The grayscale distribution histogram after image quality enhancement must fully utilize the pixel value range.

Article 23. Presentation of Frame and Surrounding Parts of Satellite Image Maps

The frame and surrounding parts of satellite image maps include:

1. Map frame, geographic coordinates, orthogonal coordinates.

2. Name and designation of the map sheet.

3. Scale of the image map.

4. Seamline table.

5. Information about the image (type of image, resolution, and time of capture).

6. Name of the unit and date of creation of the image map.

7. Coordinate system of the image map.

Article 24. Recording Data of Digital Image Maps

Digital data of image maps are recorded on CD-ROM or DVD for each map revision project. Recorded data must not contain errors and are recorded sequentially for each image map. The cover of the disc must note the complete designations of all map sheets, name of the unit, and date of creation of the image map.

Article 25. Printing Paper Image Maps

Paper image maps are printed as reference materials for off-site verification and supplementary investigation in areas requiring additional verification and investigation.

Chapter V

REMOTE SENSING IMAGE INTERPRETATION

Article 26. Remote Sensing Image Interpretation for Map Revision

Remote sensing image interpretation for map revision is conducted both indoors and outdoors. Indoor interpretation is performed for map content elements that have changed and can be accurately identified on the images. Outdoor interpretation is performed for map content elements that cannot be determined indoors or require further investigation and verification.

Article 27. Indoor Image Interpretation

1. Interpretation Materials

a) The main material is the digital image map;

b) Supplementary and supporting materials are thematic maps, GIS databases, and other types of documents;

c) The material used to record the results of interpretation is a digitized line map derived from the original map used for revision.

2. Content of Interpretation

a) Interpretation of map content elements that have changed due to non-existence or shape alteration (elements lost) to be erased from the line map and marked for deletion on the change draft with red diagonal lines for inspection purposes;

b) Interpretation of new map content elements that have appeared or undergone shape changes (new elements) and their supplementary digitization onto the line map. An object's shape is considered altered if its position on the map and on the image differs by more than 0.4 mm for clear objects and more than 0.6 mm for unclear objects.

The consolidation, removal of map content elements, and movement of positions of supplementary digitized symbols must follow the principle of prioritizing the representation of objects requiring high accuracy and significant importance. Symbols used for digitization are simple ones specifically defined in Technical Design - Budget Estimate.

c) Preparation of outdoor interpretation guidance by marking objects and features needing verification, confirmation, or supplementary outdoor work, boundaries of areas requiring supplementary surveying, and outdoor investigation routes.

Article 28. Field Survey for Aerial Mapping

1. Materials used for field survey for aerial mapping include printed satellite images on photographic paper, change maps, and field survey control sheets for aerial mapping.

2. The contents of field survey for aerial mapping include:

a) Checking the results of indoor surveying;

b) Verifying elements in the map that are still questionable from indoor surveying;

c) Supplementing elements in the map that could not be surveyed indoors;

d) Collecting information about place names, boundaries, and other data not available on the images.

3. The results of field survey for aerial mapping are recorded as follows:

a) On the printed image map, new elements in the map that have appeared, changed shape (new parts), or objects with incorrect positions are drawn;

b) On the change map, elements in the map that no longer exist or have changed shape (lost parts) are crossed out with red diagonal lines, and notes are made regarding qualitative and quantitative changes that cannot be determined from the images.

Article 29. Supplementary Surveying

Supplementary surveying is carried out for elements in the map that appear after the time of photographing and in areas lacking images due to cloud cover or glare. This surveying is conducted using GPS measurement methods, other geodetic measurement methods, or transferring from materials with equivalent accuracy.

Article 30. Completing the Results of Aerial Surveying

Completing the results of aerial surveying involves transferring the results of field surveying for aerial mapping, supplementary surveying results, and other information collected locally onto the results of indoor aerial surveying on vector map files. The method of implementation is regulated at point a and point b, Clause 2, Article 24 of this Circular.

Chapter VI

ESTABLISHING THE ORIGINAL MAP WITH CURRENTIZATION

Article 31. Establishing the Original Map with Currentization

Establishing the original map with currentization includes standardizing and re-editing the content of the vector map after completing the results of aerial surveying, according to the technical regulations for digitalizing topographic maps at scales of 1:10,000, 1:25,000, 1:50,000, and 1:100,000, issued together with Decision No. 70/2000/QĐ-ĐC dated February 25, 2000, by the Director General of the Land Administration General Department.

Article 32. Standardizing the Content of the Map

1. Structural and classification standardization includes arranging newly currentized elements in the correct data file and content layer, and correctly declaring object codes.

2. Graphic standardization includes generalizing and summarizing lines according to the regulations of topographic maps of the same scale; accurately connecting points where elements intersect or touch; linking to ensure continuous linear elements without breaks; closing off area elements; applying background patterns or colors according to regulations.

Article 33. Editing and Presenting the Map

1. Presenting elements in the map using current symbols for topographic maps of the same scale.

2. Editing to harmonize newly currentized elements with existing elements on the original map, including:

a) Editing and correcting elements in the map that are interrelated based on the principle of adjusting less accurate elements according to more accurate ones;

b) Editing and adjusting elements to ensure geographic correlation and separation between elements in the map;

c) Presenting annotations on the map consistent with newly currentized content.

3. Editing and presenting elements outside the frame according to the requirements of the currentized map.

4. Editing to link map sections according to the currentized block.

Article 34. Principles for Representing Content Elements on Maps

1. Ensure the selection, synthesis, and generalization of map content according to the regulations of the national topographic map at corresponding scales.

2. Preserve spatial relationships consistent with the general laws of terrain surfaces and objects.

3. Content elements of point type on maps shall be positioned based on the center of the symbol used for representation.

4. Content elements of linear type on maps must ensure continuity, singularity of the object, and consistency of attributes.

5. Content elements of area type on maps must be enclosed and maintain geometric correlation with other objects.

Article 35. Map Sheet Edge Matching

1. Content elements of maps between adjacent sheets within the same survey area must be matched absolutely. In cases where the positional deviation of homonymous objects does not exceed 0.3 mm on the map, the deviation may be evenly distributed to align the edges of the two sheets. If the deviation exceeds 0.3 mm, the cause must be determined for resolution.

2. Content elements of maps between sheets not within the same survey area, the permissible limits of edge matching for major and important homonymous objects are specified as follows:

a) Not exceeding 1 mm in plains areas and 1.5 mm in hilly and mountainous areas for adjacent sheets at the same scale;

b) Not exceeding 0.7 mm in plains areas and 1 mm in hilly and mountainous areas for adjacent sheets at a larger scale;

c) For concealed areas, the above limits may be increased by 1.5 times;

d) Edge matching within the specified limits shall be evenly distributed between both sides. If the limit is exceeded, the cause must be determined through a thorough review of all production stages in accordance with regulations.

If the original map does not match at the edges, it must be noted clearly as "Original document does not match" in the edge area of the sheet.

Chapter VII

PACKAGING AND SUBMISSION OF PRODUCTS

Article 36. Packaging of Products

Products submitted shall be packaged as follows:

1. CD-ROM or DVD discs containing digital product data must be high-quality discs that can only be recorded once.

a) On the cover and label of CD-ROM or DVD discs storing digital map data, the following information must be recorded: disc number, survey area name, map scale, sheet version and total number of sheets, implementation time and executing unit, recording date. Each disc must contain a directory of standard database files used. Each digital map sheet stored on the disc must be accompanied by a map history file;

b) On the cover and label of CD-ROM or DVD discs storing other types of digital product data, necessary technical information about the product must be clearly recorded to facilitate data storage and exploitation;

2. Paper products must be arranged in sequence and placed in packaging made from durable material. The packaging must indicate the survey area name, product type, scale, quantity of products, implementation time and executing unit, and any other necessary notes.

Article 37. Submitted Products

1. Satellite image control products include: layout diagram and connection measurement points for satellite and ground control images, control images, measurement books, and calculation documents for adjusting the satellite ground control network grid, and control point data files determined according to the map (if available).

2. Satellite image rectification products include: digital orthophoto file, vector map file completed according to rectification results, rectified ground control images, ground control rectification guide map, and supplementary measurement results (if available).

3. Original map data file and map history file.

4. Maps printed on paper with a weight of 100 g/m2.

5. Technical design - budget estimate.

6. Product inspection and acceptance documentation.

Chapter VIII

IMPLEMENTING PROVISIONS

Article 38. Effectiveness and Implementation Organization

1. This Circular shall take effect from June 20, 2012, and replace the relevant contents related to the rectification of topographic maps at scales of 1:10,000, 1:25,000, and 1:50,000 using satellite imagery as stipulated in the Topographic Map Rectification Regulations issued together with Decision No. 112/KT dated May 15, 1989 by the Director of the National Survey and Mapping Agency, and the Satellite Imagery-Based Topographic Map Rectification Procedure issued together with Decision No. 308/QĐ-TCĐC dated July 25, 2002 by the Director General of the Land Administration Department.

2. Any difficulties encountered during implementation shall be promptly reported to the Ministry of Natural Resources and Environment for consideration and decision.