Research On Extraction Of Mountain Peak Range Based On Grid DEM

Landform is closely related to human life,and people’s cognition of the living environment is profoundly affected by landform simulation,expression and analysis research.The terrain in China is diverse and complex,and the mountainous area covers a wide area.The research on the division and extraction of hill-position is significant to agricultural production and road planning.With the gradual deepening of landform research scale from macro to micro in recent years,the mountain peak range is the area with the most obvious surface morphological characteristics in the mountain micro landform Accurate extraction of mountain peak and mountain peak range is crucial to the efficiency of mountain micro landform classification,and is also the premise of accurate classification of hill-position.Mountain peak extraction is prone to false mountain peak and mountain peak omission.Elevation threshold is usually used to obtain mountain peak range,which separates the connection between mountain peak and mountain peak range extraction,and there are problems of subjectivity and mountain peak range uncertainty.Digital elevation model contains abundant landform information,which has obvious advantages in landform feature point extraction and micro landform division.With the support of digital terrain analysis technology,digital elevation model can be used as a data source to obtain various basic landform features,which promotes the transformation and development of micro landform classification automation and digitization of landform features.There are limitations in the methods of mountain peak extraction and mountain peak range division.Based on the theory and method of digital landform analysis,a comprehensive analysis of the surface morphological and structural characteristics of the mountain peak range revealed the aspect distribution law of the mountain peak,and created the aspect distribution feature method of mountain peak extraction with grid DEM.On the premise of accurately obtaining the mountain peaks,the mountain peak range and mountain shoulder boundary points can be obtained in multiple directions according to the variation law of mountain profile curvature transition,a boundary point search method for mountain peak range extraction based on grid DEM was established.The main work and achievements of this paper include:(1)An aspect distribution law of the mountain peak was revealed.It is generally recognized that the key to the expression of special terrain features in digital terrain analysis is to optimize the reasonable terrain factors and build a terrain feature expression model.The difference of aspect distribution feature between mountain peak and other landform feature points is found by comparison analysis of grid window.The aspect distribution of the landform points around mountain peak is more uniform than other landform feature points,and there is a law that the value of the aspect is gradually increasing in the clockwise direction with mountain peak as the center.The aspect is introduced into the extraction of the mountain peak,and the aspect expression model of the mountain point is established based on the distribution law of the aspect distribution of mountain pea k.(2)A method for mountain peak extraction based on aspect distribution feature was established.Combined with the definition that the mountain peak is the maximum elevation point,the restriction conditions for the mountain peak discrimination are set in the analysis window.The mountain peak is calculated and discriminated by the grid aspect data in the analysis window and create a method for mountain peak extraction for gird DEM based on aspect distribution feature.The experiment is set to simulated DEM and the entity DEM in two parts.The simulated DEM is used to verify the theoretical feasibility of the aspect distribution method,and the limited conditions of the mountain point aspect of the simulated DEM experiment are extended to the entity DEM,which verifies the universality of this research method.Compared with the traditional method of extracting mountain peak using relative height difference and closed contour lines,the accuracy of mountain point extraction in three experimental sample areas with different terrain relief and terrain complexity.The experimental results show that the uncertainty of threshold selection can be solved by the method for mountain peak extraction based on aspect distribution feature and improve the accuracy of mountain peak extraction.(3)A boundary point search method for mountain peak range extraction was established.In traditional classification of hill-position,there is subjective uncertainty in dividing mountain peak range by elevation threshold.On the condition of obtaining the mountain peak,the key landform feature points of the mountain profile curve are taken as the boundary points,and the mountain peak range is divided from the level of mountain geometry.Combined with DEM,which describes the properties of surface features through discrete point elevation information and based on the inflection point search algorithm of discrete point datasets,a boundary point search method for mountain peak range extraction is established.Taking the average distance from the boundary point of the mountain peak to the summit point in each direction as the boundary distance of the mountain peak range,the mountain peak range from grid DEM can be extracted,which improves the basic theoretical basis for the classification of hill-position.In this paper,an aspect distribution feature method for mountain peak extraction is proposed based on he analysis of the surface morphological structure characteristics of the mountain peak,which solves the problems of incomplete elimination of false mountain peak and omission of the peak points from the traditional extraction method.Based on the mountain peak,the boundary point search method of discrete point datasets is proposed to reclassify the mountain peak range,which solves the limitation of subjective truncation and division of mountaintop range,improves the theoretical basis of hill-position classification in digital terrain analysis,and provides a new idea for geometric classification of micro landform.