Circular No. 13/2018/TT-BTNMT on technical procedures for establishing sea surface temperature maps and chlorophyll concentration maps at the scale of 1:500,000 and 1:1,000,000 using low-resolution optical remote sensing data.

CIRCULAR

Technical regulations for the creation of sea surface temperature maps and chlorophyll concentration maps at the sea surface ratio 1:500,000, 1:1,000,000 using low-resolution optical remote sensing data

PURSUANTPursuant to Decree No. 36/2017/NĐ-CP dated April 4, 2017 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/QĐ-TTg dated December 13, 2010 of the Prime Minister on the collection, storage, processing, exploitation, and utilization of national remote sensing data and Decision No. 76 /2014/QĐ-TTg dated December 24, 2014 amending and supplementing certain provisions of Decision No. 81/2010/QĐ-TTg of the Prime Minister on the collection, storage, processing, exploitation, and utilization of national remote sensing data;Pursuant to Decision No. 83/2000/QĐ-TTg dated July 12, 2000 of the Prime Minister on the use of the National Geodetic Reference System and the National Coordinate System of Vietnam;The Minister of Natural Resources and Environment promulgates this Circular stipulating technical regulations for the creation of sea surface temperature maps and chlorophyll concentration maps at the sea surface ratio 1:500,000, 1:1,000,000 using low-resolution optical remote sensing data.

This Circular stipulates technical regulations for the creation of sea surface temperature maps and chlorophyll concentration maps at the sea surface ratio 1:500,000, 1:1,000,000 using low-resolution optical remote sensing data.This Circular applies to state management agencies and organizations and individuals related to activities of constructing and creating sea surface temperature maps and chlorophyll concentration maps at the sea surface ratio 1:500,000, 1:1,000,000 using low-resolution optical remote sensing data.

AT THE REQUEST OF THE DIRECTOR OF THE NATIONAL REMOTE SENSING CENTER, THE HEAD OF THE SCIENCE AND TECHNOLOGY DEPARTMENT, AND THE HEAD OF THE LEGAL AFFAIRS DEPARTMENT;

Low-resolution optical remote sensing datais optical remote sensing image data with a pixel size projected onto the ground larger than 100 meters.Sea surface

PART I
GENERAL PROVISIONS

Article 1. Scope of Regulation

is the surface layer of the ocean with a thickness approximately 1 millimeter.

Article 2. Applicability

Chlorophyll concentration map at the sea surface

Article 3. Explanation of Terms

In this Circular, the following terms are understood as follows:

1. is a thematic map showing information about the distribution of chlorophyll-a content in marine plants on the sea surface. Sea surface temperature map

2. is a thematic map showing information about the temperature field of the sea surface. Article 1. Sea surface temperature maps and chlorophyll concentration maps at the sea surface ratio 1:500,000, 1:1,000,000 shall be established in the National Geodetic Reference System and the National Coordinate System used for base map construction as prescribed in Decision No. 83/2000/QĐ-TTg dated July 12, 2000 of the Prime Minister on the use of the National Geodetic Reference System and the National Coordinate System of Vietnam.

3. Article 2. The reference system and coordinate system of the thematic map as prescribed in Circular No. 10/2017/TT-BTNMT dated June 6, 2017 of the Ministry of Natural Resources and Environment stipulating procedures for establishing thematic maps using remote sensing images at scales of 1:5,000, 1:10,000, 1:500,000, 1:1,000,000 (hereinafter referred to as Circular No. 10/2017/TT-BTNMT). Article 5. Form of representation of thematic maps

4. 1. The name of the thematic map includes: the theme name, the name of the area where the map is established, and the piece number (if the map consists of multiple pieces). 2. The scale of the thematic map is determined based on the area, shape, size, and level of detail of the region where the map is established.

Article 4. Mathematical Basis

3. If the thematic map consists of multiple pieces, it shall display a piece assembly diagram in the upper right corner of the map frame.

4. The thematic map shall show both the latitude-longitude grid and the kilometer grid. Latitude-longitude lines on the map are shown with a density of 1°. Kilometer grids on the map are shown with a density of 10 cm according to the map scale.

5. The legend of the map is placed on the right side of the map frame, if possible, it can be placed inside the frame at an appropriate position.

6. Temperature zones are represented on the thematic map using a red-orange color scale. Isotherms and value annotations are shown on the map in black.

7. Chlorophyll concentration zones at the sea surface are represented on the thematic map using a green color scale. Contour lines of chlorophyll concentration zones and value annotations are shown on the map in black.

3. For thematic maps consisting of multiple pieces, a piecing diagram shall be displayed in the upper right corner of the map frame.

4. Thematic maps shall display both the longitude-latitude grid system and the kilometer grid system. The longitude-latitude grid on the map shall be shown by longitude and latitude lines with a density of 1°. The kilometer grid on the map shall be shown by grid points with a spacing of 10 cm according to the map scale.

5. The legend of the map shall be placed on the right side of the map frame; if it can be arranged within the frame, the legend shall be positioned appropriately inside the frame.

6. Temperature zones on thematic maps shall be represented by an orange color scale. Isothermal lines and value annotations on the map shall be shown in black.

7. Surface water chlorophyll concentration zones on thematic maps shall be represented by a green color scale. Chlorophyll concentration zone boundary lines and value annotations on the map shall be shown in black.

Article 6. Techniques for Representing Thematic Maps

1. The thematic contents regarding temperature or surface water chlorophyll concentration on maps are calculated and extracted from low-resolution optical remote sensing data according to the model and its parameters.

2. Objects with an area ≥ 4mm² and linear objects with a length ≥ 2cm are represented on the map.

Article 7. Content Elements of Base Map Layers

1. The base map is established in accordance with the provisions of Article 9 of Circular No. 10/2017/TT-BTNMT.

2. Groups of base map data layers:

a) Mathematical base layer group including elements such as map name, map frame presentation, kilometer grid, geographic coordinate grid, notes on coordinate system, projection grid, meridian axis, map scale, method of establishment, legend, and other related objects;

b) Hydrographic layer group including basic hydrographic objects serving as a basis for indicating the position, shape, and size of thematic contents: coastline, coral reefs, rivers, sea dikes;

c) Transportation layer group including objects such as railways, expressways, national highways, waterway routes, ports;

d) Population layer group including directional population points: People's Committee headquarters, independent important landmarks, and economic, cultural-social facilities with directional significance;

đ) Topographic layer group including contour lines and depth points fully displayed like topographic maps at the same scale. For coastal topography sections (if any), they must be fully connected;

e) Administrative boundary layer group displayed up to provincial level for mainland areas, and shown up to commune level for island areas;

g) Place name annotations and explanatory notes.

3. Marine, island place names, and administrative boundaries must be updated based on the latest materials issued by the Ministry of Natural Resources and Environment.

Article 8. Content Elements of Thematic Data Layer on Surface Water Temperature

1. Areas without data.

2. For surface water temperature zoning with the smallest value range being 0.5°C.

3. Isotherms.

4. Annotations of isotherm values.

Article 9. Content Elements of Thematic Data Layer on Surface Water Chlorophyll Concentration

1. Areas without data.

2. For surface water chlorophyll concentration zoning with the smallest value range being 0.1 mg/m³.³.

3. Boundaries of chlorophyll concentration zones.

4. Annotations of zoning chlorophyll concentration values.

Chapter II
TECHNICAL REGULATIONS

Article 10. Preparation work

1. Preparation work is carried out in accordance with the provisions of Article 6 of Circular No. 10/2017/TT-BTNMT.

2. Collecting, analyzing, and evaluating materials including: Remote sensing images, maps, statistical data, and information related to the thematic map to be established.

3. Collecting direct measurement data of surface water temperature (if available), chlorophyll content at the site (if available).

4. Determining types of remote sensing data and acquisition cycles to serve the establishment of thematic maps.

Article 11. Scientific Editing

1. Scientific editing is carried out in accordance with the provisions of Article 7 of Circular No. 10/2017/TT-BTNMT.

2. Determining the name, scale, and map fragment division (fragment numbers are sequentially numbered in Roman numerals from left to right, top to bottom); displaying the frame, longitude-latitude grid, and presentations outside the map frame.

3. Determining representation criteria, content layout, and product map format.

4. Determining the map establishment phase, calculating the number of cycles and start and end times of each cycle.

5. Writing detailed editing plans.

6. Designing and creating symbol libraries.

7. Organizing data storage directories.

Article 12. Editing Base Maps

1. Scanning and aligning in cases where paper maps are used as reference materials for creating base maps.

2. Aligning coordinate systems if necessary.

3. Merging and cutting data according to the scope of specialized map creation.

4. Editing, generalizing, and selecting objects according to detailed editing plans.

Article 13. Acquiring and Processing Remote Sensing Data

1. Acquiring remote sensing data during the map creation phase, including: remote sensing image data and supplementary data.

2. Steps for processing remote sensing data

a) Converting the reference system of remote sensing data;

b) Removing all pixels identified as clouds, without value, or land;

c) Calibrating images: converting image grayscale values to top-of-atmosphere reflectance values;

d) Correcting multi-scattering atmospheric noise;

đ) Correcting atmospheric absorption radiation;

e) Correcting bidirectional reflectance distribution;

g) Correcting solar glint effects.

3. The positional accuracy of images after processing shall not exceed one (01) pixel.

Article 14. Extracting Sea Surface Temperature Specialized Content

1. Selecting models and model parameters based on the type of remote sensing images used.

2. Selecting image channels: Image channels chosen to calculate temperature values fall within the thermal band from 11-14µm.

3. Calculating sea surface temperature at the time of image capture based on the selected model and image channels.

4. Creating sea surface temperature images according to cycles

Depending on the requirements of the map to be created, select the following steps:

a) Creating daily images;

b) Creating weekly images (combining seven days' images in a week). Weekly sea surface temperature images are calculated as the average of images in the week;

c) Creating monthly images (combining images of days in a month). Monthly sea surface temperature images are calculated as the average of images in the month;

d) Creating quarterly images (combining images of days/months in a quarter). Quarterly sea surface temperature images are calculated as the average of days or months in the quarter;

đ) Creating annual images (combining images of days/months/quarters in a year). Annual sea surface temperature images are calculated as the average of days, months, or quarters in the year;

e) Creating images for a period (combining images of days in a period). Periodic sea surface temperature images are calculated as the average of images in the period.

5. Interpolating isothermal lines and thermal image zoning

a) Interpolating isothermal lines from the set of pixel values of periodic sea surface temperature images;

b) Zoning thermal images with the smallest zoning interval being 0.5°C;

c) Converting thermal zoning regions from raster form to vector form.

Article 15. Extracting Surface Water Chlorophyll Content Specialized Content

1. Selecting models and algorithms based on the type of remote sensing images used.

2. Selecting image channels: Image channels chosen to calculate surface water chlorophyll content fall within the wavelength range from 443-565nm.

3. Calculating surface water chlorophyll content at the time of image capture based on the selected model, image channels, and algorithm.

4. Creating chlorophyll content surface water images according to cycles

Depending on the requirements of the map to be created, select the following steps:

a) Creating daily images;

b) Creating weekly images (combining seven days' images in a week). Weekly surface water chlorophyll content images are calculated as the average of images in the week;

c) Creating monthly images (combining images of days in a month). Monthly surface water chlorophyll content images are calculated as the average of images in the month;

d) Creating quarterly images (combining images of days/months in a quarter). Quarterly surface water chlorophyll content images are calculated as the average of days or months in the quarter;

đ) Creating annual images (combining images of days/months/quarters in a year). Annual surface water chlorophyll content images are calculated as the average of days, months, or quarters in the year;

e) Creating images for a period (combining images of days in a period). Periodic surface water chlorophyll content images are calculated as the average of images in the period.

5. Zoning chlorophyll content images

a) Calculating surface water chlorophyll content values and dividing them into regions with the smallest division interval being 0.1mg/m3;

b) Converting chlorophyll content zoning regions from raster form to vector form.

Article 16. Standardization of derived data, integration, analysis, comprehensive processing of data, and editing, presentation of thematic maps

1. Standardization of derived data, integration, analysis, comprehensive processing of data, and editing, presentation of thematic maps shall be carried out in accordance with Articles 13, 14, and 15 of Circular No. 10/2017/TT-BTNMT.

2. Content for building detailed editing plans

a) Develop guidelines for editing including the following contents: determining indicators to be expressed and requirements for the completeness of content elements, methods of expression, classification rules for content elements, types, colors, sizes of symbols, accuracy requirements;

b) Establish a symbol library on computers and create author templates, symbol templates, legend templates in software used for editing original author maps;

c) Design temperature layer color scales and surface water chlorophyll content;

d) Determine map creation technology and solutions for uploading to the Internet.

3. Content for editing original author digital maps

a) Edit geographic base elements: edit, generalize, and select objects suitable for surface water temperature content and surface water chlorophyll content according to the detailed editing plan;

b) Edit thematic content elements: integrate thematic elements on the base map to ensure geographic correlation between thematic elements and base elements; represent thematic elements using the system of symbols designed in the detailed editing plan.

4. Content for building map history files

a) Each thematic map must have an accompanying file about its history;

b) The map history file must include the following information: Name of agency or individual creating the map; Time, method, scope of map creation; Mathematical basis of the map: coordinate system, projection grid, central meridian, map scale; Data sources used to create the map; Technical issues arising during map creation and solutions; Agency inspecting and accepting the map;

c) The map history file is saved in *.doc or *.txt format.

5. For printed thematic maps: editing work for printing must comply with general principles for editing printed thematic maps and follow technical design - budget regulations for thematic maps.

6. Steps for implementing electronic thematic maps on CD-ROM and on the Internet

a) Design interface;

b) Identify and program interactive tools on the map;

c) Program display of edited digital author maps and link map components;

d) Package CD-ROM or publish the map on the Internet.

Article 17. Building explanatory reports for thematic maps

The work of building explanatory reports for surface water temperature maps and surface water chlorophyll content maps is carried out in accordance with the provisions set forth in Article 16 of Circular No. 10/2017/TT-BTNMT.

Article 18. Product inspection and acceptance

1. The basis for inspection is the technical design - budget for creating thematic maps that has been approved by competent authorities.

2. Inspection and acceptance procedures for products

a) Inspection and acceptance at the construction unit level;

b) Inspection and acceptance at the project owner level;

c) Review and acceptance of product quality and quantity documentation.

3. Inspection contents

a) Accuracy and completeness of mathematical basis elements, geographic base elements, specialized elements according to the technical design - budget and correctness, completeness, and geographic correlation suitability between thematic elements and geographic elements;

b) Correctness, completeness, and suitability of the legend;

c) Correctness, completeness of classification and stratification of thematic content objects in map files;

d) Correctness and completeness in representing thematic content elements using the designed symbol system;

đ) Rationality in the layout presentation of thematic maps.

4. Types of products to be inspected

a) Paper maps: inspect printed inkjet copies;

b) Digital maps: inspect map files on computers;

c) Remote sensing image data, maps on CD-ROM and on the Internet must be inspected on computers. Internet maps must be directly inspected in the Internet environment to test links and transmission speed.

Article 19. Submission and storage of products

1. Submitted products

a) The submitted product is a technical inspection product that has been accepted at various levels as prescribed by the Ministry of Natural Resources and Environment;

b) Types of data used to create thematic maps: Original data used to create base maps, remote sensing data used to create maps, sea surface temperature images, chlorophyll concentration surface water images;

c) Printed thematic maps: Quantity of 03 (three) sets;

d) Digital maps stored on data carriers and internet maps must store all author's digital maps, symbol libraries, map profiles, image files, articles, source code of the interface and product packaging. The digital product set must have labels clearly showing information: Map creation area, map name, map scale, map creating agency, creation time. Quantity to be submitted: 03 (three) sets;

đ) Thematic map explanatory report: Quantity of 03 (three) sets;

e) Inspection and acceptance file of the product.

2. Thematic maps must be stored for at least: The agency creating the thematic map and the Remote Sensing Information and Data Center under the National Remote Sensing Center.

Chapter III
IMPLEMENTING PROVISIONS

Article 20. Effective Date

This Circular takes effect from November 3, 2018.

Article 21. Organization of Implementation

Clause 1. Ministries, ministerial-level agencies, government-affiliated agencies, People's Committees of provinces and centrally governed cities, and related organizations and individuals are responsible for implementing this Circular.

2. The National Remote Sensing Center shall be responsible for guiding and inspecting the implementation of this Circular.

3. In case the legal normative documents referred to and applied in this Circular are amended, supplemented, or replaced, they shall be implemented according to the provisions of the new document.

4. During the implementation of this Circular, if there are difficulties, agencies, organizations, and individuals shall promptly reflect them to the Ministry of Natural Resources and Environment for consideration and decision./.