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I have the following problem [in QGIS]. In displaying two raster layers (topographic maps), a white area appears between the two. If I apply transparency to one of the layers, this white area still hides the union of the contour lines. Is there a way to see these layers together without having to apply transparency? With orthographic layers the visibility of the fold is perfect without having to resort to transparency.


El problema que tengo es el siguiente; cargo dos capas raster (planos topograficos)aparece entre la unión de ambos una zona en blanco. Si aplico la trasparencia a una de las capas dicha zona blanca deja vislumbrar la unión de las curvas topográficas. ¿ Existe la forma de ver dicha unión de capas sin tener que aplicar la transparencia?. Con capas ortograficas la visibilidad del pliege es perfecto sin tener que recurrir a la traspariencia. Gracias.

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If the raster images have white borders, perhaps the first thing to try is to crop them off. Raster -> Extraction -> Clipper, and select just the map area.

If the width of the white borders varies it will not be possible to do this so you will have to make the white borders transparent. Load one of the images, right-click on it in the layers panel, select "Properties" and then click the "Transparency" tab. You will see a group of four icons, click on the one with the arrow and the question mark, then click on the white border. After that, click "OK". This should make the white borders transparent.

The problem appears to be similar to this one. But in your case the borders are white rather than black.


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Open the Layer Properties dialogue by double clicking your raster. In the transparency tab, set "no data value" to 0. This worked for my problem with an NAIP base map photo.

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