Question

假设我有一个通过

派生的以下格式的矩阵

https://www.mediafire.com/file/n1bds3eo7n8p34c/Bank_Farm_2_elev.tif

    setwd("D:/Gs Data")
    require(raster)
    require(rgdal)

    GDALinfo("Bank_Farm_2_elev.tif")
    DEM <- raster("Bank_Farm_2_elev.tif")
    test_xyz <- rasterToPoints(DEM)
    colnames(test_xyz) <- c("xt", "yt", "Elev")

    plot(DEM,
    maxpixels=ncell(DEM),
    col = grey(1:100/100),
    main= "LIDAR data")

目的是从左下角到右上角提取横断面。计算点之间的最小距离，并从第三列获取该位置的值。因此，从第3列创建1D横断面数据。简单说明：

draw_1

我在matlab中找到了以下代码来执行此操作：

％将横断面上每个点的测量值放在一个名为zt

的变量中

    for (j in 1:528) { % assuming nr of points for the transect. Transect 
    coordinates in xt and yt
      myMinDist=9999999 % initialise the variable to a very large number
      for (i in 1:length(text_xyz)) { % assuming the amount of points in the 
    whole dataset to search trhough and find the point that lies on the 
    transect
        if ((sqrt((xt(j)-x(i))^2+(yt(j)-y(i))^2))<myMinDist){ % test to try 
    and get the point closes to our transect point xt(i) and yt(i)
          myMinDist=sqrt((xt(j)-x(i))^2+(yt(j)-y(i))^2) % update minDist
          zt(j)=(zi)
          }
      }
    }

我试图将R重新写入附加的.tif数据文件

    for (j in 1:528) { # the number of rows when dataset is plotted as .tif 
    file (given by 'dimensions' in the GDALInfo() command)
      for (i in 1:length(test_xyz)) { # although length of test_xyz does not 
      line up with ncell?
        if ((sqrt((test_xyz["xt"][j]-x[i])^2+(test_xyz["yt"][j]-y[i])^2))
    <myMinDist) {
          myMinDist=sqrt((test_xyz["xt"][j]-x[i])^2+(test_xyz["yt"][j]-y[i])^2)
        } else { 
          test_xyz["Elev"][j]=(zi)
        }
      }
    }

我认为我缺少的关键点是设置一个空向量来编写输出，以及在代码中分配xt和x，yt和y，zt和z之间的正确区别。期待建议。

问候。

在计算空间样带中点之间的最小距离后提取值

0 个答案: