【教程】11-ParaView将航天雷达地形数据进行可视化处理

SRTM数据可以从Shuttle Radar Topography Mission的官方网站下载。

SRTM的HGT格式是一个由1201x1201个坐标点组成的二进制文件，采用大端序（Big endian）存储。

import sys

nrows = ncols = 1201

xdim = ydim = 0.000833

args = sys.argv

filename = args[1]

name, ext = os.path.splitext(filename)

outname = name + '.csv'

longitude = float(name[1:3])

latitude = float(name[4:7])

print('longitude: ' + name[0] + name[1:3])

print('latitude: ' + name[3] + name[4:7])

ulxmap = longitude + (xdim/2.0)

ulymap = (latitude+1.0) - (ydim/2.0)

a = array.array('h')

f = open(filename, 'rb')

a.fromfile(f, nrows*ncols)

f.close()        

a.byteswap()

alist = a.tolist()

out = open(outname, 'w')

count = 0

for row in range(nrows):

    for col in range(ncols):

        x = ulxmap + xdim * col

        y = ulymap - ydim * row

        z = max(0.0, alist[count])

        out.write(str(x) + ',' + str(y) + ',' + str(z/10000.0) + '\n')

        count += 1

    if count%100000 == 0:

        print(str(int(100.0 * count/(nrows*ncols))) + '%')

print('100%')

print('node number: ' + str(count))

out.close()

执行以下命令：

python hgtToCSV.py N32E020.hgt

将N32E020.hgt转换为N32E020.csv。注意：转换后的坐标可能不准确，实际使用时请确保转换为正确的坐标。  

接下来，将CSV文件转换为ParaView可以读取的VTS格式（VTK的结构化网格数据格式）。这里也使用一个简单的Python脚本来完成转换。

import os.path

import sys

from paraview.simple import *

paraview.simple._DisableFirstRenderCameraReset()

args = sys.argv

filename = args[1]

workingDir = './'

fileName = args[1]

csvReader = CSVReader(FileName=[workingDir + fileName + '.csv'])        

csvReader.DetectNumericColumns = 1

csvReader.UseStringDelimiter = 1

csvReader.HaveHeaders = 0

csvReader.FieldDelimiterCharacters = ','

csvReader.MergeConsecutiveDelimiters = 0

tableToStructuredGrid = TableToStructuredGrid(Input=csvReader)

tableToStructuredGrid.WholeExtent = [0, 1200, 0, 1200, 0, 0]

tableToStructuredGrid.XColumn = 'Field 0'

tableToStructuredGrid.YColumn = 'Field 1'

tableToStructuredGrid.ZColumn = 'Field 2'

calculator = Calculator(Input=tableToStructuredGrid)

calculator.AttributeMode = 'Point Data'

calculator.CoordinateResults = 0

calculator.ResultNormals = 0

calculator.ResultTCoords = 0

calculator.ResultArrayName = 'z'

calculator.Function = 'coordsZ'

calculator.ReplaceInvalidResults = 1

calculator.ReplacementValue = 0.0

SaveData(workingDir + fileName + '.vts', proxy=calculator,

        Writealltimestepsasfileseries=0,

        DataMode='Appended',

        EncodeAppendedData=1,

        CompressorType='ZLib')

使用ParaView安装文件夹中的pvpython执行脚本：

pvpython csvToVts.py N32E020

转换完成后，将生成N32E020.vts文件。

将上述步骤生成的N32E020.vts文件加载到ParaView中，即可进行可视化。