1
vote
2answers
40 views

qgis raster style 'no data value' checkbox is ignored - what's a good workaround?

See bug report filed here: http://hub.qgis.org/issues/10236 Note the initial bug report got 'fixed' but that fix introduced this new error, so the issue was reopened a few days ago. Anyway, it ...
0
votes
0answers
29 views

Disable option in QGIS which picks 4th band as alpha band

Is there a way to disable that function? As somebody who works with 4 band orthoimagery on a daily basis, it is annoying to go to the transparency options every time I load an image to disable the ...
1
vote
0answers
43 views

QGIS 2.01 - raster transparency not working properly

I have loaded a color raster image (aerial orthoimagery) into a QGIS project. The layer is visible but very transparent (in the enclosed image the vector polygons are below the imagery), but when I ...
2
votes
1answer
130 views

How to change layer transparency without changing border lines?

I have a raster image of elevations. I have added a vector shapefile that contains local political divisions. I want to keep the elevation colors, but I want to keep the black lines representing the ...
2
votes
1answer
148 views

Change Values of Georeferenced Raster

I am using QGIS to georeference B&W images. I have now done this and would like to set the black surround of the image (as a result of the georeferencing) to transparent but this does not work as ...
2
votes
0answers
192 views

How to render a transparent raster layer on top of one or more vector layers with PyQgis?

I been trying to render a map with a 3 vector layers and one raster layer. The idea is that the raster layer should be on top of the other 3 vector layers. The problem is that even when I add the ...
0
votes
0answers
70 views

QGIS: “No data” raster value for missing rows conflicts with data?

I’m having a problem with specifying “no data” in a raster dataset in QGIS 1.8.0-Lisboa. QGIS does fine in interpreting pixels I don’t have rows for as “no data” if I set Layer Properties -> ...
1
vote
1answer
139 views

Scanned Transparent Map Overlay

We have a flat file of 50 Geology maps that have a transparent overlay with faults and drill holes. I have them scanned and georeferenced as TIF images and they will be used in ArcGIS 10.0, 10.1 and ...
6
votes
3answers
2k views

How to make transparent the background of a topographic map in QGis 1.8.0?

I'm starting to use QGis 1.8.0. I have a raster topographic map, i.e. white background and black contour lines, houses, roads and so on. I want to make transparent the white background, so if I ...
1
vote
2answers
442 views

How to surround a clipped raster with transparency? (gdalwarp)

I am trying to perform the following task, but it does not seem to work: I have got a raster file (raster.tif) containing an aerial photo, which I want to clip using a Shape file (clip.shp) that ...
1
vote
1answer
183 views

Why is transparancy of GRASS rasters missing when imported into QGIS?

I have a raster map in QGIS imported from a GRASS mapset with the QGIS GRASS plugin. The problem is that I have null() cells in the GRASS map that appear "colored" in QGIS. How can I set the ...
1
vote
2answers
1k views

QGis problem with raster transparent

I am new to QGIS. I found the problem impossible to solve the parts of raster data that are in TIFF format should be made transparent. What do I do?