RGB TIF到GeoTIF并删除背景色

如何解决RGB TIF到GeoTIF并删除背景色

我已经使用matplotlib python三角函数创建了tif图像，现在需要将tif更改为带有epsg4326投影的goetiff，并移除背景，仅需要补丁。

我面临什么困难： 1-投影变化发生不正确。 2像素值应为z参数值。 3-仅是我不想的整个拉特朗区域的片段。

代码：- 1-用于在下面创建matplotlib三角tiff代码

#MAKING TIFF FILE USING TRIANGULARION MATPLOTLIB.
import matplotlib.tri as mtri
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

def plot():

        x=np.random.uniform(70,94,74)
        y=np.random.uniform(8,22,74)

        # A selected triangulation of the points.
        triangles = np.asarray([
            [67,66,1],[65,2,66],[1,2],[64,65],[63,3,64],[60,59,57],[2,64,3],[3,63,4],[0,67,[62,4,63],[57,56],[59,58,[61,60,69],69,60],[4,62,68],[6,5,9],68,62],[69,61],[9,70],8,7],70,5],[8,6,[56,56,52],[70,10,[54,53,55],55,53],[68,[52,[11,12],71,13,[10,13],[51,50,[13,71],[12,[71,52,50],14,[50,49,[49,48,[14,16,15],48],[17,19,18],20,19],[48,14],47,16],[47,46,[16,45],[23,24],[21,24,22],[20,17,25,[27,26,28],72,21],[25,21,72],[45,20],28,26],[44,73,[72,45,73],[28,29],[29,31],[43,44],[73,43,40],39],31,25],[42,40,43],[31,30,[39,41,33,[32,33],38,[33,38],34],[37,35,[34,35],[35,37,36]])
        z = np.random.uniform(0.5,74)

        triang = mtri.Triangulation(x,y,triangles=triangles)
        print("type(triang):",triang)
        print("type(z):",type(z))

        ax=plt.tripcolor(triang,z,vmin=0,vmax=2)
        ax
        plt.savefig("ax.tif")
        plt.show(ax)
        
plot()

2-用tif投影制作Geotiff

from osgeo import gdal,osr
import numpy,gdal

ds = gdal.Open('ax.tif')
band = ds.GetRasterBand(1)
myarray = numpy.array(band.ReadAsArray())
convert=lambda x:x*(0.0124796)

myarray=convert(myarray)

#print("myarray:",myarray)
selection = numpy.logical_or(myarray >= 3.5,myarray <= 7)

new_array = [ [0 for i in range(band.XSize)] for j in range(band.YSize)]

for i,item in enumerate(myarray):
    for j,element in enumerate(item):
        if selection[i][j] == True:
            new_array[i][j] = myarray[i][j]
        else:
            new_array[i][j] = -999
            if new_array[i][j]==3.182298:
                new_array[i][j] = -999
                
            

geotransform = ds.GetGeoTransform()
wkt = ds.GetProjection()

# Create gtif file
driver = gdal.GetDriverByName("GTiff")
output_file = "ax_geotiff.tif"

dst_ds = driver.Create(output_file,band.XSize,band.YSize,1,gdal.GDT_Float64)

new_array = numpy.array(new_array)


print(type(new_array[i]))

#new_array[i]=new_array.max())
    
    
    

#transformed_arr = np.where(arr<5,arr*10,0)
#new_array=numpy.where(new_array[i]==new_array.max(),-999,new_array)
print("new_array:",new_array)
#writting output raster
dst_ds.GetRasterBand(1).WriteArray( new_array )
#setting nodata value
dst_ds.GetRasterBand(1).SetNoDataValue(-999)
#setting extension of output raster
# top left x,w-e pixel resolution,rotation,top left y,n-s pixel resolution
dst_ds.SetGeoTransform(geotransform)
# setting spatial reference of output raster

srs = osr.SpatialReference()
srs.ImportFromEPSG(4326)
#srs = osr.SpatialReference()
#srs.ImportFromWkt(wkt)
dst_ds.SetProjection( srs.ExportToWkt() )
#Close output raster dataset

ds = None
dst_ds = None

print(numpy.unique(new_array))

3-绘制Geotiff

#CHECKING THE TIFF FILE / ANALYSING THE TIFF FILE DATA AND PLOT.
#tttraster_geotiff

import gdal
%matplotlib inline
import rasterio
from matplotlib import pyplot
import numpy 

ds = gdal.Open('ax_geotiff.tif')
band = ds.GetRasterBand(1)
myarray = numpy.array(band.ReadAsArray())
print(myarray)

pyplot.imshow(myarray,cmap='pink')

pyplot.show()

##上面是我正在使用的示例数据和代码，但是我没有得到正确的epsg 4326投影，如果我选择cmap ='jet'，则我的背景色为geottiff蓝色，即将出现，即geotiff图的蓝色很大一部分表示z参数的mav值，如果我更改为np.nan则为蓝色，则ia看不到其他颜色，

那么我必须做的所有修改都是- 1-正确的投影 2-仅删除蓝色作为难处理的颜色。enter image description here enter image description here 3-想要删除那种红色（z变量的最大值），只有我想要的地图。

enter image description here