图片/nparray转成shapefile文件

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前言

一、数组转成shapefile文件函数

第一步：使用cv2.findContours把图片轮廓

这些轮廓contours是一个list，list里面是array。array格式是（x,y）类似坐标

第二步：把数组转成gdal用的数据

把contours的（x,y）点，保存起来，按照如下格式，保存在binary_value.txt中

x0 y0
x1 y1
x2 y2

第三步：从txt中取数据使用gdal生成shapefile文件

def nparray2shp(file_path_jpg, folder_2_shpimg, DATASET, Imarray):
    Image.fromarray(np.uint8(Imarray)).save(file_path_jpg)
        
    #.jpg trans to .shp
    np.set_printoptions(threshold=np.inf)
    img = cv2.imread(file_path_jpg)
    gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    ret, binary = cv2.threshold(gray,127,255,cv2.THRESH_BINARY)
    contours, hierarchy = cv2.findContours(binary,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
    cv2.drawContours(img, contours, -1, (0, 0, 255), 1)
    cv2.imwrite(folder_2_shpimg+DATASET+'_contour.jpg', img)
    
    # (binary) is the binary image; contours's class is List 
    file = open('binary_value.txt', 'w')    
    for i in range(len(contours)):
        for j in range(len(contours[i])):
            temstr = str(contours[i][j])+'\n'
            temstr=temstr.replace('[','')
            temstr=temstr.replace(']','')
            temstr = temstr.split()
            file.write(str(temstr[0]+ ' '+str(temstr[1]))+'\n')
    file.close()
    
    gdal.SetConfigOption("GDAL_FILENAME_IS_UTF8","NO")
    gdal.SetConfigOption("SHAPE_ENCODING","GB2312")
    ogr.RegisterAll()
    srs = osr.SpatialReference()
    srs.ImportFromEPSG(4326) 
    driver = ogr.GetDriverByName("ESRI Shapefile")
    dataSource = driver.CreateDataSource(folder_2_shpimg+DATASET+".shp")   
    layer = dataSource.CreateLayer(DATASET, srs,ogr.wkbPoint)    
    field_list = []    
    f_name= ['x_long','y_lat']
    for i in range(len(f_name)):       
       field_name = f_name[i]
       field_list.append(field_name)
       field = ogr.FieldDefn(field_name, ogr.OFTString)
       field.SetWidth(100)
       layer.CreateField(field)
     
     # row and col
    file2 = open('binary_value.txt', 'r')
    for line in file2:
        feature = ogr.Feature(layer.GetLayerDefn())
        geom = ogr.Geometry(ogr.wkbPoint)
        geom.AddPoint(float(line.split(' ')[0]), -float(line.split(' ')[1])) 
        feature.SetGeometry(geom)         
        for j in range(2):
             feature.SetField(field_list[j], line.split(' ')[j])
        layer.CreateFeature(feature)
    os.remove('./binary_value.txt')
    os.remove(file_path_jpg)

效果图