如何使用matplotlib-basemap正确投影tif图像

Question

我尝试使用gdal和matplotlib-basemap显示光栅图像。

我在这里解释一下我的尝试使用basemap.interp函数，对于我的过程的总结构化概述，请查看我的IPython Notebook。 首先是我加载和投影栅格的代码。

# Load Raster
pathToRaster = r'I:\Data\anomaly//ano_DOY2002170.tif'
raster = gdal.Open(pathToRaster, gdal.GA_ReadOnly)
array = raster.GetRasterBand(1).ReadAsArray()
msk_array = np.ma.masked_equal(array, value = 65535)
print 'Raster Projection:\n', raster.GetProjection()
print 'Raster GeoTransform:\n', raster.GetGeoTransform()

# Project raster image using Basemap and the basemap.interp function
map = Basemap(projection='robin',resolution='c',lat_0=0,lon_0=0)

datain = np.flipud( msk_array )

nx = raster.RasterXSize
ny = raster.RasterYSize

xin = np.linspace(map.xmin,map.xmax,nx) # nx is the number of x points on the grid
yin = np.linspace(map.ymin,map.ymax,ny) # ny in the number of y points on the grid

lons = np.arange(-180,180,0.25) #from raster.GetGeoTransform()
lats  = np.arange(-90,90,0.25) 

lons, lats = np.meshgrid(lons,lats) 
xout,yout = map(lons, lats)
dataout = mpl_toolkits.basemap.interp(datain, xin, yin, xout, yout, order=1)

levels = [-1000,-800,-600,-400,-200,0,200,400,600,800,1000]
cntr = map.contourf(xout,yout,dataout, levels,cmap=cm.RdBu)
cbar = map.colorbar(cntr,location='bottom',pad='15%')

# Add some more info to the map
cstl = map.drawcoastlines(linewidth=.5)
meri = map.drawmeridians(np.arange(0,360,60), linewidth=.2, labels=[1,0,0,1], labelstyle='+/-', color='grey' ) 
para = map.drawparallels(np.arange(-90,90,30), linewidth=.2, labels=[1,0,0,1], labelstyle='+/-', color='grey')
boun = map.drawmapboundary(linewidth=0.5, color='grey')

这将绘制以下内容：

特别清楚地看到，在北美和南美的东海岸，光栅数据和海岸线有一个偏移。

我对如何调整我的代码毫无头绪，因此我的数据将在正确的投影中进行转换。

值得的是：My used raster tif file（如果你下载的话，在'a-no_DOY'之后'ano_DOY ..'之前在'a'和'no'之间放' - '）

Answer 1

我不确定你自己插补/重新投影的错误，但它可以做得更简单。

contourf接受latlon关键字，当为true时，接受lat / lon输入并自动将其转换为地图投影。所以：

datain = msk_array

fig = plt.figure(figsize=(12,5))
map = Basemap(projection='robin',resolution='c',lat_0=0,lon_0=0)

ny, nx = datain.shape

xin = np.linspace(map.xmin,map.xmax,nx) # nx is the number of x points on the grid
yin = np.linspace(map.ymin,map.ymax,ny) # ny in the number of y points on the grid

lons = np.arange(-180,180,0.25) #from raster.GetGeoTransform()
lats  = np.arange(90,-90,-0.25) 

lons, lats = np.meshgrid(lons,lats)

xx, yy = m(lons,lats)

levels = [-1000,-800,-600,-400,-200,0,200,400,600,800,1000]
cntr = map.contourf(xx, yy,datain, levels,cmap=cm.RdBu)

cbar = map.colorbar(cntr,location='bottom',pad='15%')

# Add some more info to the map
cstl = map.drawcoastlines(linewidth=.5)
meri = map.drawmeridians(np.arange(0,360,60), linewidth=.2, labels=[1,0,0,1], labelstyle='+/-', color='grey' ) 
para = map.drawparallels(np.arange(-90,90,30), linewidth=.2, labels=[1,0,0,1], labelstyle='+/-', color='grey')
boun = map.drawmapboundary(linewidth=0.5, color='grey')

请注意，我更改了lats定义，以便删除输入栅格的翻转，这只是个人偏好。