Python geographic data processing 21: batch operation based on arcpy (3)

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1. Implementation 1 (advanced usage of batch cropping)

Realize that all provinces in the given .shp file are used as the clipping range, the given .tif file is clipped, and individual .tif files of all provinces are output:

# -*- coding: cp936 -*-
import arcpy

arcpy.CheckOutExtension('Spatial')

# 定义输入文件的路径
shp_path = r"C:\Users\map.shp"
tif_path = r"C:\Users\dem.tif"

# 读取文件
shp = arcpy.mapping.Layer(shp_path)
tif = arcpy.Raster(tif_path)

# 获取.tif 文件的空间参考信息
spatial_ref = tif.spatialReference

# 创建一个用于存储输出的文件夹
output_folder = r"C:\Users\output"
arcpy.CreateFolder_management(output_folder, "clipped_tifs")

# 循环遍历 .shp 文件中的每个省份
for row in arcpy.da.SearchCursor(shp, ["SHAPE@", "name"]):
    # 构建输出.tif 文件的路径
    output_tif_path = output_folder + "\\clipped_tifs\\" + row[1] + ".tif"
    
    # 使用.shp 文件对.tif 文件进行裁剪
    arcpy.Clip_management(tif_path, "#", output_tif_path, row[0], "#", "ClippingGeometry")

    # 打印输出信息
    print row

# 删除中间变量
del shp, tif

2. Implementation 2 (summation of grid calculator)

Realize the raster calculation and summation of tif images with the same first 14 characters in the file name:
such as: XXXX_XXX_2003.M01_Mean, XXXX_XXX_2003.M02_Mean, XXXX_XXX_2003.M03_Mean; XXXX_XXX_2004.M01_Mean, XXXX_XXX_2004. M02_Mean, XXXX_XXX_2004.M03_Mean; XXXX_XXX_2005.M01_Mean, XXXX_XXX_2005. M02_Mean, XXXX_XXX_2005.M03_Mean. . . . . .

# -*- coding: cp936 -*-
import arcpy
import os

arcpy.CheckOutExtension('Spatial')

# 设置工作空间
arcpy.env.workspace = r"D:\Datasets"

# 获取所有.tif文件
tif_list = arcpy.ListRasters("*", "TIF")

# 创建字典，用于存储同一年份的栅格图像
tif_dict = {
    
    }

# 遍历所有.tif文件，将同一年份的栅格图像添加到字典中
for tif in tif_list:
    year = tif.split("_")[2][:4]
    if year in tif_dict:
        tif_dict[year].append(tif)
    else:
        tif_dict[year] = [tif]

# 对每个年份的栅格图像进行栅格运算求和，并保存结果
for year in tif_dict:
    tif_sum = None
    for tif in tif_dict[year]:
        tif_path = os.path.join(arcpy.env.workspace, tif)
        tif_raster = arcpy.Raster(tif_path)
        if tif_sum is None:
            tif_sum = tif_raster
        else:
            tif_sum += tif_raster
    output_name = "D:\\Datasets\\TIFClip\\" + year
    output_path = os.path.join(arcpy.env.workspace, output_name)
    tif_sum.save(output_path)
    print year

3. Implementation 3 (Use the Raster Calculator to delete the specified value)

1. If we want to delete a certain empty value or specified value in the attribute table of the raster image, such as 9999 or 52668, if we operate in arcgis, we can use the raster calculator and enter the following code:

Con((input.tif != 9999) & (input.tif != 52668), input.tif)

2. You can also use arcpy for batch processing:

# -*- coding: cp936 -*-
import arcpy
import os

arcpy.CheckOutExtension("spatial")
# 定义输入和输出文件夹
input_folder = r"D:\Datasets"
output_folder = r"D:\Datasets\tifclipCon"

# 循环遍历文件夹下的所有tif文件
for filename in os.listdir(input_folder):
    if filename.endswith(".tif"):
        # 构建输入和输出路径
        input_path = os.path.join(input_folder, filename)
        output_path = os.path.join(output_folder, filename)

        # 使用Map Algebra表达式删除指定的属性表值
        expression = "Con((\"" + input_path + "\" != 9999) & (\"" + input_path + "\" != 52668), \"" + input_path + "\")"
        arcpy.gp.RasterCalculator_sa(expression, output_path)
        
        print filename

4. Realize four (read tif files in two folders to multiply and save)

Read the tif files in two folders and multiply the two corresponding files:

# -*- coding: cp936 -*-
import arcpy
import os
import warnings
warnings.filterwarnings('ignore')

arcpy.CheckOutExtension('Spatial')

# 设置工作空间
arcpy.env.workspace = r"D:\RSE\dataset\1\output"

# 设置输入文件夹路径
t_folder = r"D:\RSE\dataset\t\output"
p_folder = r"D:\RSE\dataset\p\output"

# 设置输出文件夹路径
out_folder = r"D:\RSE\dataset\tbyp"

# 获取输入文件夹中以TEM开头的tif文件列表
t_list = arcpy.ListRasters("TEM*", "TIF")

# 遍历输入文件夹中的tif文件
for t_file in t_list:
    
    # 获取tif文件名的后三个字符
    suffix = t_file[3:6]
    
    # 构造PRE文件路径
    p_file = os.path.join(p_folder, "PRE" + suffix + ".tif")
    
    # 判断PRE文件是否存在
    if not arcpy.Exists(p_file):
        print("PRE file does not exist for " + t_file)
        continue

    print "*******************************************************************"
    # 构造输出文件路径
    out_file = os.path.join(out_folder, "output" + suffix + ".tif")
    
    # 使用栅格计算器对两个tif文件进行相乘
    expression = "Times('{}', '{}')".format(t_file, p_file)
    arcpy.gp.RasterCalculator_sa(expression, out_file)
    
    print "Processed " + out_file

This code uses the Times() function to multiply two rasters

5. Realize five (add all tif files in the folder)

Add all tif files in the folder:

# -*- coding: cp936 -*-
import arcpy
import os

arcpy.CheckOutExtension('Spatial')

# 设置工作空间
arcpy.env.workspace = r"D:\RSE\dataset\TbyP"

# 设置输出文件夹路径
out_folder = r"D:\RSE\dataset\TbyP"

# 获取输入文件夹中的所有tif文件
tif_list = arcpy.ListRasters("*", "TIF")

# 如果没有tif文件，则输出提示信息
if not tif_list:
    print("There are no TIFF files in the input folder.")
else:
    # 构造栅格计算器表达式
    #expression = " + ".join(tif_list)
    expression = ' + '.join(['"' + tif + '"' for tif in tif_list])

    # 构造输出文件路径
    out_file = os.path.join(out_folder, "outputAll.tif")

    # 使用栅格计算器对所有tif文件进行相加
    arcpy.gp.RasterCalculator_sa(expression, out_file)

    print"The output file is located at " + out_file