HJ 1166-2021National Ecological Status Survey and Evaluation Technical Specifications-Ecosystem Remote Sensing Interpretation and Field Verification (English PDF)

6.1.2 Data Preprocessing

By performing radiometric correction, geometric precision correction, atmospheric correction, image registration, image fusion, band synthesis, A series of processing such as image enhancement, stitching and cropping forms image data suitable for interpretation, and the specific basis for remote sensing data quality control the relevant requirements of HJ 1176 are implemented, and the preprocessing method can be implemented with reference to the relevant requirements of DD.2013-12 and TD/T 1055.

6.2 Establish a classification system

The classification is established according to the requirements of interpretation integrity and the number of complex features depicted, the description depth and details of the state of the elements, etc.

This standard mainly adopts the national two-level classification system, which is divided into 8 grades I and 24 grades II. Please refer to the appendix for the specific index system.

A in Table A.1.

6.3 Establishing Interpretation Flags

Interpretation marks are image features that can directly or indirectly reflect and discriminate ground object information, mainly including shape, size, shadow, tone, Direct signs such as color, texture, pattern, location, layout, etc. and indirect signs such as water system, landform, vegetation, etc., for interpretation of signs, please refer to GDPJ 06 the relevant requirements are implemented to form the interpretation target feature table, see Table B.1 in Appendix B for details.

6.4 Interpretation of human-computer interaction

6.4.1 Information Source Preparation

6.4.1.1 According to prior knowledge, select, analyze, compare, reason and judge the characteristics of various objects on the image, and then classify them according to the system adjusts the feature categories.

6.4.1.2 Describe various relationships on the image, including.

a) point, line and surface relationship on the image;

b) The distribution relationship of the spectral curves of various types of ground objects in different coordinate systems;

c) The relationship between different geographical elements, such as the relationship between water systems, topography, and surface cover;

d) Changes and connections of various ground objects in time and space.

6.4.1.3 From a systematic geoscience point of view, explain and comprehensively analyze the attributes, categories and relationships on the image, and get regular knowledge and and valuable conclusions.

6.4.2 Image Interpretation System

Related software and hardware systems for processing remote sensing images.

6.4.3 Interactive environment

Visualization environment using remote sensing and geographic information systems.

6.4.4 Interactive mode

An interpretation method combining bottom-up control and top-down control is adopted.

6.4.5 Interpretation of human-computer interaction

6.4.5.1 Combine the visual interpretation and processing process to improve the automatic classification system.

6.4.5.2 Integrate multi-source reference data, such as information between remote sensing information or between remote sensing and non-remote sensing information, to form a new set of spatial information.

information, a new composite image.

6.4.5.3 Use reference data and automatic classification system to perform automatic interpretation of remote sensing images, and finally perform visual interpretation and adjustment.

7.1 Field verification steps

7.1.1 Determining the verification area

The verification area is determined according to basic geographical features such as verification objectives, regional climatic conditions, physical geography, and landforms.

7.1.2 Choosing a sampling method

The sampling method is selected according to the structure of the ecosystem, the characteristics of the landscape pattern, and the geographic complexity of the verification area. Serving Ecosystem Types There are three main sampling methods for ground inspection.

a) Simple random sampling is to randomly select n samples from N points in the population, and each sample has an equal probability of being selected.

in areas with fewer populations;

b) Systematic sampling is to draw samples from the population according to a certain sampling interval, which is suitable for areas with a large number of populations (such as large homogeneous area);

c) Stratified sampling is to divide the population into several types according to attribute characteristics, and then randomly select samples from each type.

An area composed of several parts with obvious differences (such as a complex terrain area or an interlaced zone, etc.).

7.1.3 Spatial Design of Sampling Points

According to the total sample space, spatial representativeness and historical survey data, plan the spatial distribution of sampling points to meet the total sample size Design requirements, an average of not less than 1 verification point per 100 km2.

7.1.4 Determining the verification time and route

7.1.4.1 Determine the verification time according to the remote sensing images.

7.1.4.2 Determine the specific route of the ground inspection according to roads, water systems, population concentration, interpretation signs and mission requirements, etc.

Examination of GDPJ 11 related requirements.

7.1.5 Sampling check

According to the ground inspection results, combined with the sample point information, the accuracy of the ecosystem type of the sample point is verified, and the ecosystem type field is formed.

For the detailed checklist, see Table C.1 in Appendix C for details.

7.2 Field verification index system

The field verification indicators of ecosystem types are shown in Table 1.The field verification indicators of ecosystem types include. positioning information, natural geographical factors and Ecosystem type.

7.3 Field Verification Technical Methods

7.3.1 Positioning Information

Use GPS and other positioning tools and other auxiliary information to obtain the latitude and longitude coordinates of the sample points (using 2000 national geodetic coordinates) and elevation and other information and record.

7.3.2 Physical Geographical Factors

The topography, landform, climate, vegetation, water source and other physical and geographical features of the sample sites were investigated and recorded by the observation method.

7.3.3 Ecosystem types

Based on tools and materials such as GPS, cameras, record books, interpretation signs, and related professional books, through simple random sampling, systematic sampling the sample points and transect lines are arranged in a combination of sampling and stratified systematic sampling methods, and field visual judgment, unmanned aerial vehicles, and high-spatial-resolution images are used.

and other means, obtain the ecosystem type and fill in the detailed verification form of the ecosystem type in the field, see Table C.1 in Appendix C for details.

7.4 Accuracy Verification

Combined with high spatial resolution remote sensing images and field inspection site photos, the interpretation results of each sample point are compared, and the positive interpretation results of each type are compared.

The percentage of the correct sample points to the total number of sample points is used as the interpretation accuracy, and the Kappa coefficient is used for auxiliary verification. Statistical records for each ecosystem the interpretation accuracy of the traditional type requires that the interpretation accuracy of the first-level type of the ecosystem reaches 95%, the second-level type reaches 85%, and the interpretation accuracy is not reached.

Re-interpret it to achieve the interpretation accuracy, and fill in the field accuracy verification form for ecosystem types. See Appendix C for details.

in Table C.2 and Table C.3.