9.5.1 Remote Sensing Interpretation
9.5.1.1 Remote Sensing Data Preparation
In order to meet the requirements of the work objectives and work scale, TM data is selected as the main data source for remote sensing interpretation. TM data of multiple time phases in the work area can be selected to meet the multi-temporal comparison requirements of remote sensing interpretation.
9.5.1.2 Data Processing
Using graphic image processing software such as ENVI, ERMAPPER, etc., TM and IRS data are geometrically corrected, radiometrically corrected, and aligned in order to eliminate geometric aberration and radiometric aberration, which in turn creates the conditions for the matching of image to image, image to topographic map, and other thematic maps, and the creation of image maps, etc., and also creates conditions for the automatic extraction and classification of remote sensing information. Remote sensing information automatic extraction, classification and statistics to prepare.
(1) Geometric correction polynomial operation
In order to eliminate the geometric distortion of remote sensing data and ensure the accuracy of the analysis and research results, both aviation and aerospace remote sensing data need to be geometrically corrected. The geometric correction of remote sensing images is generally processed by indirect method, i.e., the correction polynomial coefficients are solved according to the control points, and the functional equation of coordinate transformation between the map space and image space of the control points is established. The technical route of correction is in the rough processing of remote sensing image and map, for the whole image frame, according to the selection rules of control points to select the control point pairs, respectively, read out the coordinates on the map or reference image (x, y) and the row and column numbers on the remote sensing image to be corrected (u,v), then the image data coordinates (u,v) and the map coordinates (x,y) of the function between the equation:
u=F(x,y)<
v=G(x,y)
This relation is usually expressed by a polynomial:
Geology of the ecological environment of northeastern Hainan Island
In which: ui,vi are the image coordinates of the ith point (row and column numbers); xi,yi are the ground coordinates corresponding to the ith point (which can be the latitude/longitude coordinates, or the geodetic coordinates); an,bn,n =1,2,3,... are polynomial coefficients.
With the above control point coordinates, the coefficients of the polynomials are obtained by the method of least squares, and the coefficients obtained and the determined coordinate conversion function are used for the coordinate transformation of the whole area, i.e., the spatial position of each image element is solved according to the transformation function, so as to achieve the purpose of correction.
(2) Selection of Ground Control Points
Selection of ground control points is the most important step in geometric correction, and its accuracy will directly affect the correction accuracy of the whole data space, and the accuracy of the future points and the area accuracy. We adopt the following principles: first, the ground control points are evenly distributed in the image, without the sense of sparse and dense; second, the control points have obvious and precisely positioned identification marks on the image to ensure the accuracy of spatial alignment; third, the control points have a certain number of guarantees. For image and map calibration, there are 15 pairs of control points can meet the calibration accuracy, but also to ensure that the computer's operating speed.
The amount of remote sensing data is very large, in addition to choosing the right number of control points can ensure the operation speed, how to improve the speed of coordinate transformation and realize large format geometric correction on the microcomputer, is the central problem of geometric correction. Each time the satellite transits, there is a certain offset and rotation, and even if the ground station is coarsely corrected by Gauss-Krüger map projection, the coarsely processed remote sensing image is still deviated from the due north direction by an angle. The same view of different transit time has a large offset, at present, due to the satellite itself, the angle of deviation and the degree of offset is getting bigger and bigger, resulting in the alignment between the image and the image, the image and the map of the correction have a large amount of rotation and translation workload.
(3) Selection of sampling method
The last step of geometric correction is resampling. After the transformation and localization of the pixel distribution in the image is not uniform, the need to establish a new grid of the image, each image according to certain rules of gray-scale interpolation calculation to re-assign the value of the composition of the new image matrix, it should be seen that the resampling of the classification accuracy and image information will have a certain impact. The image element is a composite information, a kind of integrated luminance information. Although the brightness value of the image element is resampled as the brightness value of the new correction point, the image element is corrected, but its composite information or comprehensive brightness coefficient has also changed, and the information has also changed accordingly. Therefore, the question is what sampling method to choose to minimize this change. There are more sampling methods, but the most commonly used are the nearest-neighbor method - assigning the spectral intensity of the nearest neighbor to each new dot; bilinear interpolation - interpolating from four neighboring points; and triple convolutional interpolation - interpolating three times from 16 surrounding points.
In order to better retain the original information and try to avoid the increase of new mixed image elements, from the above three resampling methods, the latter two methods need multiple surrounding image elements to participate in the interpolation to get the new luminance value, thus generating a new mixed image element, while the closest neighbor method just gives the spectral value of the intensity of the closest neighbor to the new point, there is no arithmetic but just moving, and there is no generation of new mixed image elements, and the closest neighbor method produces the least effect on the The nearest neighbor method has the least impact on classification accuracy and image information, and is a reliable method for geometric correction resampling.
9.5.1.3 Image Production
(1) Color Synthesis Processing
TM image data*** has seven bands, which have different sensitivities to various feature information, of which the sixth band (TM6) is a thermal infrared band, because of its low resolution, without special needs are not generally involved in the color synthesis process, usually from the remaining six bands. Usually, 3 bands are selected from the remaining 6 bands for color synthesis, and 20 combination schemes can be obtained. In order to meet the needs of remote sensing application research and provide the most abundant and useful information, the best band combination must be selected according to the actual needs. There are two methods for selecting the best bands: one is the experimental comparison method, which determines the best combination scheme based on the visual interpretation effect through multiple combination image processing; the other is the statistical analysis method, which quantitatively analyzes and comprehensively evaluates from several aspects such as the width of the information domain reflected by the bands, the correlation between the bands, and the entropy value of a subset of the band combination data. Among them, the three bands covering the widest spectral range, the best information entropy, and the smallest correlation with each other are generally the best band combinations. Experiments show that the TM5.4.3 band combination is the most informative, the band combination image of the near infrared strong reflection of the vegetation is green, the near infrared band strong absorption of the water body is dark blue and blue-black, rocks, soil brown or reddish-brown, white clouds are white, very close to the effect of natural color. Therefore, it is also called simulated natural color. Choosing TM5.4.3 (R.G.B) band combination for color synthesis processing, this image has bright hue, moderate contrast, clear image, rich extractable information, and good decoding effect.
(2) Image digital mosaic processing
Image digital mosaic processing method: a high-quality remote sensing mosaic image should have three basic conditions: information-rich; color tone harmony, a perfect blend; mosaic geometry with high precision. In order to meet these conditions, the ideal practice is to select those images with small geometric distortion, high image quality (no noise, no clouds), and the same or similar imaging time. In fact usually this ideal selection is difficult to realize. Due to the different time and seasons, and the changes in the landscape caused by human activities, the images of several landscapes will change in color tone, texture and even the content of the features, which will bring great difficulties to the image mosaics. We have adopted our own digital mosaic method to better solve this problem, the specific measures are as follows: ① Optimal combination of bands and color synthesis scheme selection. According to the aforementioned, we chose the TM5.4.3 (R.G.B) band combination, which will not be repeated here. ② The sampling interval is 1 × 1 pixel sampling at full resolution. It can be maximized to ensure that the original recorded information is not lost. ③ Image pre-processing. In order to ensure the image quality, the 4-scene image is inspected wave-by-wave before mosaicing, and the identified problems are processed by de-banding and de-noising, and the geometric alignment between the waves is performed. ④ One-level hue matching, in order to ensure that the hue of the 4-scene image is basically consistent, first of all, histogram matching is carried out between adjacent images, taking the mean and variance of the gray level of the image pixel of one scene as the reference standard, and transforming the value of the gray level of the image pixel of the other scene, so as to make it converge to the mean and variance, and to make the hue close to the same. ⑤ Geometric alignment. The inherent scanning error of the sensor, the change of the flight attitude of the platform and the offset of the satellite orbit often cause the geometric aberration of the image between adjacent orbits, resulting in the misalignment of the overlapping area of adjacent images. For this reason, the same features are selected as control points within the overlapping area of adjacent graphics, and the selected control points are used as benchmarks for tracking and mosaicing, so as to achieve the purpose of geometric alignment. (vi) Selection of optimal stitching points. Although all the processing is done well, it is difficult to eliminate the seam phenomenon due to the existence of the difference in the gray value of adjacent images, for this reason, when splicing, we should try to avoid those parts of the image where the difference in the gray value is relatively large, and look for the parts of the smallest gray value to be spliced, so that it is possible to eliminate the seam phenomenon. To this end, the use of a sliding window in the image overlap area line by line, pixel by pixel to search for the smallest difference in gray value of the pixel as a splicing point, so that the seam phenomenon has been maximized to improve. (vii) Secondary hue matching. Through further smoothing, it can further eliminate the residual grayscale difference within the specified range on both sides of the splicing point after the first level of hue matching, so that the seam phenomenon can be further improved.
Generation of mosaic image and evaluation of mosaic geometric accuracy: The geometric accuracy of mosaic image depends on the selection accuracy of the control points on the overlapping area of the two scenes being mosaiced adjacent images. In order to evaluate the geometric accuracy of the mosaic image, we randomly select several sub-areas and identify the same feature points on the original image and the mosaic image respectively, and *** select 40 feature points with the same name, and calculate the mean-square error according to their coordinate values.
(3) Image Editing and Output
Using NEVI and PHOTOSHOP image processing software, the map is adjusted for color, contrast, and saturation, and goes through the process of notation and finishing, so that the whole image is consistent in tone, coordinated and beautiful. After that, the use of high-precision digital image output equipment - H.P Designjet 5500 PS 5000RS type laser digital imager output image, to ensure the geometric accuracy and quality of the output image.
9.5.1.4 Image Enhancement Processing and Information Extraction
In carrying out the process of image decoding, in order to improve the decipherability of the image to achieve the purpose of extracting certain useful information, we have done the following image enhancement processing.
(1) Ratio Image Processing
Using the difference in spectral reflectance brightness values of the same feature in different bands, we divide the pixel value of one band by the corresponding pixel value of another band to get a new image. The blackest and whitest parts of the gray value after ratio processing indicate the greatest difference in spectral reflectance between the two bands. The processed image has the same ratio value for the same feature, which is independent of sunlight, so the shadow effect can be eliminated. The purpose of extracting the same kind of features is achieved. The pseudo-color image synthesized by the processed TM5, 4 and 3 bands, the white part reflects the sandy land, the green part shows the vegetation, and the blue-black color is the water body.
(2) Thresholding
For images processed by linear stretching, logarithmic transformation or the original image, using the histogram, the brightness information related to the sanded land is selected and given a certain threshold, and the processed image is obtained to highlight the desertified land type more, which achieves a good application effect.
9.5.1.5 Remote Sensing Interpretation
(1) Principle of Remote Sensing Image Interpretation
The main task of applying remote sensing technology for ecological geology research is to extract information through image interpretation and computer image processing, and to describe the type, nature, quality of various ecological geological problems and their location in space in the form of line drawing, graphic symbols and textual notations, Distribution law to describe, so that the remote sensing image into various types of professional maps.
Remote sensing image feature recognition: image features are the direct signs to identify and distinguish various ground objects, mainly in hue (or color), shape, size, shadow pattern, pattern, shadow, related position and other image features that can be directly observed and measured on the image. The establishment of a certain feature interpretation mark, often need to be based on the image spectral characteristics, imaging season, imaging time, a variety of direct signs of the combination of relationships and field field verification and other factors to determine.
Remote sensing image interpretation principles: ① image features comprehensive analysis. From the imaging principle, spectral characteristics, imaging season, imaging time, image markers and key interpretation of the combination of markers and other aspects of the comprehensive analysis, try to exclude multiple interpretations. From the known to the unknown, in order to further improve the credibility of the interpretation. ③ Combine indoor interpretation with field investigation and verification, and combine impact analysis with field sampling and analyzing results, to remove falsehoods and preserve the truth, in order to reveal the meaning of the image. ④Visual interpretation combined with computer image processing to enhance image information enhancement processing and information extraction to reflect the scientific and advanced methods and means.
Remote sensing image interpretation methods: ① Direct interpretation method. According to the different resource types in the image of the visual image characteristics, to capture the main interpretation of the mark, after comparative analysis, to determine the specific types of features. ② Logical reasoning method. According to the image mark and its surrounding related features image characteristics of logical reasoning judgment, so as to achieve the purpose of identifying specific features. ③ Multiple information comparison method. Through multi-temporal remote sensing image comparison, remote sensing image comparison with related professional drawings and related textual information, in order to achieve the purpose of qualitative and quantitative analysis of the interpretation target.
(2) Remote Sensing Interpretation Signs
Because of the dense vegetation in the tropics, the regional distribution of plants reflects the geological and geomorphological parts to a certain extent. Many factors such as topography, geomorphology, vegetation and so on can be considered comprehensively, and based on the actual work experience and field field investigation, multiple elements of remote sensing interpretation markers can be established for multi-temporal TM remote sensing images.
1) Interpretation markers of ecological and geological background units:
Granite rainforest area in the middle mountains: dark green, uniform in color, distributed along the peaks and ridges in the form of a ring or an oval, with sparse gullies.
Granite low mountain rainforest area: dark green, more uniform color, distributed around the peaks and ridges, showing sparse small patches, small gullies began to develop at lower elevations.
Granite-sand shale low hills sparse scrub area: light green, sometimes there are dendritic, irregular light purple, light white patches, dendritic water system development, the development of small gullies in general.
Granite - sand shale low hills grassland area: green, dark green, distribution of more light purple fine patches, the topography of the small ups and downs, gullies are not developed.
Gravel layer terrace grassland area: light purple, green, white mixed, forming irregular flower patch, parallel dendritic water system.
Granite mound shrub-steppe zone: light green with numerous light purple and white floras, small washes developed.
Granite low hills artificial forest area: green, on which numerous small patches of both dark green and light purple, washouts are sparse and irregular.
Granite low hill economic forest area: green and dark green, with many dark patches and a few light white patches, dendritic water system, and undeveloped gullies.
Basalt-gravel layer terrace economic forest park: dark green, with extremely regular fine grid as the distinctive feature, mostly distributed around the reservoir.
Granite hills farming area: green dominated, mixed with light purple, light white and other colors, fine mottled shadow pattern, light purple, often worm-like spread along the small rivers and gullies, irregular dendritic water system, small gullies extend longer.
Basalt-gravel layer terrace plains cultivated area: light green, green mainly, mixed with a large number of light purple, light white patches, when the more regular fine mesh lattice or speckled, patchy, etc., water system varies greatly.
River floodplain area: light green and blue color is dominant, on both sides of the river or estuary distribution.
②Remote sensing interpretation signs of features:
Rivers, lakes: black, rivers are curved, lakes are irregular patches.
Roads: white regular straight or curved lines.
Villages and towns: light purplish-red, with many light-colored patches around them in a very fine, indistinct grid, connected to traffic lines.
Agricultural land and cultivated areas: light green color, basically regularly distributed around villages and towns.
Aquaculture areas: dark black in color, separated by some more regular structures.
Mountainous areas: covered with vegetation, greenish in color, in which shadows can be seen.
Sandy beaches (beaches, river beaches): white or yellowish-white in color, banded.
Wash: black and white, dendritic and faceted.
Littoral shelterbelts: dark green, distributed along the coastal zone, mixed with a few square light-colored patches.
Mangrove belt: dark green, distributed in the low part of the coastal harbor, with uniform surface color, small area, and many serpentine creeks within it.
3 Remote sensing interpretation of key issues:
Erosion zone: light green, with a large number of light white and light purple-red patches distributed on it, in the form of a flower pattern, in which the white patches (non-vegetated areas) are especially large and irregularly shaped to distinguish them from the cultivated land, and the white patches are mostly developed in the small gulleys.
Deserted areas: due to the high reflectivity of the sand, sandy areas are very characteristic of white, a closer look for the size of the white patches gathered. It is distributed along the coast in a speckled pattern.
Woodland degradation area: the green color tone is light and there are more light purple, violet and white patches on the green background.
Coastal erosion zone: the coastline is in a very characteristic concave arc towards the continent, with a smooth shoreline and a thin white line (high reflectivity of the coastal beach) separating the sea from the land.
(3) Field Survey and Verification
Field survey and verification includes two stages: initial field survey, establishment of interpretation markers and later field verification.
After each subject has been evaluated by the design and the content of investigation and research has been clarified, on the basis of obtaining image data and preliminary indoor interpretation, the initial field reconnaissance will be carried out to familiarize with the geography and geology environment, to understand the overview of the regional geology and environmental geology as well as the unification of the understanding, and to establish the interpretation mark, so as to lay the foundation for the indoor image interpretation and the compilation of the interpretation map.
Field checking and verification work, on the basis of the compilation of indoor image interpretation sketches, on-site investigation and verification and sampling of key ecological and environmental geological problems and interpretation objects that have not yet been clarified, further clarifying various interpretation signs and supplementing and perfecting the interpretation maps through the investigation.
(4) Thematic map production
Image scale: the scale of satellite images and topographic maps used for remote sensing interpretation is the same as that of topographic maps used in the field, both of which are 1:100 thousand. The preparation of thematic maps is generally based on image interpretation, topographic maps as a carrier, on a microcomputer using specific software to interpret the contents of the mapping to 1:100,000 geographic base map. And for the local area of the content of the slightly larger scale interpretation in accordance with the 1:50,000 satellite image map.
Satellite image map production: satellite remote sensing image map image, intuitive, information-rich and as a variety of research content of the interpretation of the logo, but also to understand the face of the region to grasp the macro information. Select multiple time-phase (at least two) multi-view TM data, the production of 1:100,000 satellite remote sensing image maps and key areas of 1:50,000 satellite image maps.
Computer-assisted compilation of interpretation maps: In order to make the remote sensing interpretation results map specification, serialization and informationization, it is recommended to adopt Map-GIS system to computerize the remote sensing ecological and geological interpretation content, and establish corresponding graphic files, so as to provide convenience for the reuse of the above results maps. In the process of mapping using this system, the geographic base map and the interpreted maps of various ecological and geological problems are digitized in layers respectively. Multi-layer data files are formed and edited into ecological and geological remote sensing maps of the work area on this basis.
9.5.2 Regional ecological and environmental geology field survey
Regional ecological and environmental geology field survey is a comprehensive field filling of various contents of ecological and environmental geology, and its methods and technical requirements can refer to the relevant requirements of "Technical Requirements of Regional Ecological and Environmental Geological Survey" (the first draft of the solicitation of opinions) and "Technical Requirements of 1:250,000 Regional Geological Survey" of the Geological Survey of China. According to our working experience, the regional ecological environment geological survey should be carried out in the area which has carried out regional geology and regional hydro-industrial-environmental geology surveys of the same scale, and on the basis of which we adopt the method of compilation and measurement, focusing on the investigation of geomorphological patterns, quaternary geology, environmental geology, soil geology and environment, tourism geology, geological hazards, etc., and draw the investigation contents on the topographic map to provide information for the preparation of the final ecological environment geological results. Provide information for the final ecological environment geological results.
Before the field survey, it should fully collect and analyze the existing information, carry out remote sensing interpretation, understand the ecological and environmental geology of the survey area and the existing problems, and carry out the field mapping with focus and clear purpose.
9.5.2.1 Filling scale
1:250,000 ecological and environmental geological survey hand map should adopt 1:50,000 topographic map. In practice, 1:100,000 topographic map has been used as the field map, due to the low precision, terrain, features and field relative deviation, but also not conducive to the field route investigation.
9.5.2.2 Division of ecological geological mapping unit
After comprehensive consideration, this ecological geological survey adopts the three major elements of topography, lithology, and vegetation type to form an ecological geological unit, in which topography and geomorphology are the first element, lithology is the second element, and vegetation is the third element, e.g., for a certain unit, the combination of all the elements is named as the granite lowland rainforest area. Forested area. A certain ecological geological unit reflects the natural climate, geological structure, anthropogenic activities and other factors.
9.5.2.3 Determination of the precision of survey points and lines
Precision of survey points and lines: ecological environment geological survey does not engage in the average distribution of points, and on the basis of remote sensing interpretation to find out the regional ecological environment geological conditions, it carries out the key survey work in the key areas, with the aim of finding out the state of ecological environment geology. In principle, each kind of ecological environment geological unit must be controlled by survey points, and the accuracy of survey points on the surface is 1 to 2 per 100km 2 in the plain area and 2 to 3 per 100km 2 in the mountainous and hilly area. The investigation route is generally based on the vertical geomorphological boundaries of the traversal method, supplemented by the tracing method.
9.5.2.4 Drawing of Ecological Geological Profile
The ecological environment geological profile should be perpendicular to the ecological environment geological units and geomorphological boundaries, and traverse different geomorphological and ecological environment geological units in the survey area as far as possible. The profile line can be selected according to the actual situation of a combination of long and short lines. The profile reflects the geology, geomorphology, plants, soil, land use conditions and so on. Requirements for the entire survey area at least 2 to 3 controlling ecological environment geological profile, key areas mapping large-scale ecological environment geological profile.
9.5.3 Soil Nutrient and Geochemical Survey
Soil nutrient and geochemical element content constitutes the basic agricultural characteristics of the soil, which is an important part of the ecological environment geological survey, and its survey content and the ecological environment geological field survey synchronized with the survey method and technical requirements can be carried out in accordance with the "Technical Requirements of Regional Ecological Environment Geological Survey" (the first draft of the solicitation of opinions). Its investigation methods and technical requirements can be carried out according to the relevant requirements of "Technical Requirements for Regional Ecological Environment Geological Survey" (the first draft for comments). Due to the abundant rainfall in the tropical area, the slope residual layer and weathering layer are thicker, and the leaching effect of the soil is strong, the investigation of the soil environment is different from other regions.
9.5.3.1 Soil Nutrient Survey
Soil nutrient surveys are carried out through spot sampling tests. Soil nutrients are distributed in the O or A layer of the soil, generally at a depth of 0 to 30 cm, which is the second environmental layer of the soil. Due to the strong leaching in tropical areas, the distribution layer of nutrients is slightly deeper than in general areas, and the sampling depth can be deepened appropriately.
Soil nutrient analysis items: organic matter, ammonium nitrogen, nitrate nitrogen, effective P, fast-acting K, slow-acting K, effective S, effective Si, effective B, effective Mo, effective Cu, effective Fe, effective Zn, effective Mn, effective Ca, effective Na, effective Mg, effective Li. According to the actual needs of the investigation to add or subtract the analytical items.
9.5.3.2 Soil geochemical investigation
Soil geochemical investigation should be closely integrated with the geochemical investigation of water system sediments, in order to provide some basic geochemical information for the basic research of ecological environment geology (groundwater environment, soil environment, medical environment). Soil geochemical investigation should take samples in layers, with the second environmental layer representing the current situation and the first environmental layer representing the background. Due to the strong leaching effect in the tropics, the sampling depth can be deepened appropriately.
Soil geochemical analysis items: silicon, aluminum, iron, calcium, magnesium, titanium, potassium, sodium, manganese, phosphorus, copper, lead, zinc, chromium, nickel, cobalt, vanadium, strontium, barium, tungsten, boron, molybdenum, fluorine, cadmium, beryllium, arsenic, antimony, bismuth, chlorine, mercury, sulfur, nitrogen, selenium, lithium, pH value. According to the needs of the actual investigation of the need to increase or decrease the analysis of the project, select the environmental plants and the environment beneficial and harmful elements, analyze its effective state.
9.5.3.3 Sampling requirements for soil survey
Soil samples can be taken as single-point samples or multi-point mixed samples. The measured value of multi-point mixed sample is equivalent to the average value of several points, which is more representative, and it is recommended to adopt this method of sampling. The depth and weight of the soil at each sampling point should be uniform, and the ratio of the upper and lower layers of the soil sample should be the same. The sampling tool is a Luoyang shovel or hoe.
Each mixed sample take about 1kg. If there are too many sampling points and make too many mixed samples, you can put all the soil samples on a plate or plastic sheet, crushed and mixed by hand, and eliminated by tetrad method. The method of quadrature is: the collected soil samples are crushed, mixed well, spread into a quadrilateral, divided into four parts as in the shape of a field, retaining the diagonal two parts of the soil sample, mixed well and left as a sample, while the other two parts are discarded. If a sub-take is still too much soil samples, can again 4 points, until the weight of 1kg until. Soil samples can be contained in cloth bags or wide-mouth plastic bottles, inside and outside the bag or plastic bottle, each with a label, with a pencil indicating the sampling location, date, sampling depth, soil name, number and sampling people. At the same time, according to the soil survey requirements, do a good job of sampling point soil profile related description.
9.5.3.4 Sampling precision requirements
1:250,000 ecological environment geological survey, nutrient and chemical probe samples are taken as the sampling control unit of the soil unit (soil subclass), and the sampling point should be combined with the ecological environment geological survey point, and the sampling point precision requirement is consistent with that of the ecological environment geological survey point, i.e. every 100km. If the area of soil unit (soil subclass) is large, the precision requirement of sampling point is consistent with the precision requirement of ecological environment geological investigation point, i.e. it is appropriate to control 1~3 sampling points per 100km 2, and there is at least 1 soil sample for each soil type. In the soil sample to take the code sample 5%, for quality monitoring.
9.5.4 Rock and mineral testing
Soil effective state analysis see forestry soil analysis, agricultural chemistry, agricultural geology, environmental protection and other relevant standards and monographs. Various evaluation parameters and a variety of "leaching" methods, testing techniques are also many, for different purposes and objects of work. According to the target geochemical samples of regional survey needs, with reference to the national standards and agriculture, forestry, environmental protection and other relevant departments of the "protocol" and other relevant information, selected to forestry soil analysis method of national standards (now changed to the industry standard) and (agriculture) soil chemical analysis monographs as a blueprint for the basic analysis of the soil effective state method.
The full-scale analysis of major soil nutrients, except humus, has ready-made standard analytical methods. Conventional elements are analyzed according to the analytical methods of the 1:200,000 Regional Geological Survey.
See Table 9.4 for details of the analytical methods of soil effective state and full analysis of major nutrients and Table 9.5 for the detection limits of the methods.
Table 9.4 Table of analytical methods of soil effective state and full analysis of major nutrients
Table 9.5 Table of detection limits of the analytical methods of soil effective state and full analysis of major nutrients
9.5.5 Other methods of investigation
Ecological Environment Geological survey has a wide range of contents, and only by applying multiple survey methods can the ecological environment quality of the survey area be more comprehensively surveyed and evaluated. According to the tropical ecological and geological characteristics of the northeast of Hainan Island, the ecological and environmental geological survey of the Qionghai Range focuses on several ecological and environmental geological problems and soil environment that have a greater impact on the survey area on the basis of a basic understanding of the ecological and environmental geology of the survey area, and the methods used are not comprehensive enough, so geophysical exploration, drilling and other important methods can be used according to the content of the ecological and environmental geological survey. In addition, this Qionghai amplitude survey is divided into zones according to the natural ecological characteristics and intensity of human activities, highlighting the key issues of each zone, such as the division into urban environmental geology survey area, coastal zone ecological environmental geology survey area, tropical rainforest ecological environmental geology survey area, and tropical agriculture (crops) ecological environmental geology survey area.
The urban environmental geology survey area focuses on the investigation of hydrogeological characteristics of urban water supply, engineering geology and stability of rock and soil bodies, environmental geological conditions and problems; earthquakes and volcanoes, ground deformation, marine power disasters and other geological disasters; the impact of human engineering activities on the geologic environment; the relationship between economic development and resources; and the impact of wastewater, waste gas and garbage on the environmental geology.
Coastal zone ecological and environmental geology survey area is located in the range of 10-20km inland from the multi-year average high tide line, which focuses on the investigation of Quaternary geological features, river channel change, coastal change, environmental geology; coastal tourism geological resources, intertidal landforms, mangrove forests ecological and environmental geology; water supply hydro-geological conditions, engineering geological conditions, and agro-geological problems.
Tropical rainforest ecological and environmental geology survey area focuses on the investigation of tropical rainforest species, distribution range; rainforest growth area geological background; the role of tropical rainforest on the quality of the ecological environment; soil erosion, collapse and environmental geologic disasters.
Tropical agriculture (crop) ecological environment geological survey area focuses on the investigation of tropical agriculture, crop resources; Quaternary geology and geomorphology, soil type, geochemical background and soil nutrient conditions; agricultural hydrogeological conditions; agricultural surface water resources; soil erosion, land sands; pollution of water resources for agricultural irrigation, soil contamination; the interrelationship between crop nutrients and soil nutrients.