QGIS : Merge two layers using Raster calculator include NoData values 合併圖層

Press Ctrl+Alt+M open commander

Open Processing algorithm: Raster calculator

QGIS 2.10.x

• Main input layer 

Select first input layer ( as variable a, DEM, sea level == NoData )

Sea = white area

ImageMagick : Image split in two halves 左右分割

convert [path][filename.extension] [-options] -crop 2x1@ -set filename:tile "%t_%[fx:not(page.x)]" "[path]%[filename:tile].[extension]"

Split file into two images for right [filename_0] and left [filename_1].

Example :

convert image.png -crop 2x1@ -set filename:tile "%t_%[fx:not(page.x)]" "%[filename:tile].png"

Result : Right side image_0.png and left side image_1.png 

 convert image.jpg -crop 2x1@ -set filename:tile "%t_%[fx:not(notpage.x)]" "%[filename:tile].jpg"

Result : Left side image_0.jpg and right side image_1.jpg

QGIS : Merge two layers using Raster calculator 合併圖層

Press Ctrl+Alt+M open commander

Open Processing algorithm: Raster calculator

QGIS 2.10.x 

• Main input layer 

Select first input layer ( as variable a, high resolution DEM, sea level == 0 )

QGIS : Set Zero values to Null using Raster calculator 替換數值

Press Ctrl+Alt+M open commander

Open Processing algorithm: Raster calculator

QGIS 2.8.x 

QGIS 2.10.x