Tagged Questions

0
votes
0answers
31 views

Worsened image quality and flase colours after georeferencing

When I georeference a map of vegetationtyps (about 20 colours, each representing a certain vegetation) the quality of the georeferenced map is really bad and the some colours has changed (e.g. black ...
2
votes
1answer
36 views

What defines a Class in the Heat map plugin?

What defines a Class in the Heat map plugin? As in: "Black holes like that are usually caused by raster values exceeding the range of the color ramp. Try adding another class with a higher associated ...
4
votes
2answers
99 views

How to create a colormap where colors diverge at value 0 in QGIS?

I calculated a raster as difference of two other rasters. Now I want to create a colormap where one colour represents negative values and one colour positive ones. The two colours should become ...
1
vote
2answers
83 views

Put color for raster data(aspect.tif) on QGIS1.8.0

I create aspect.tif from DEM file. I could put the values(0 to 360)from contrast enhancement. I could set color from color map(freakout or Pseudocolor). In here, the data is shown by only 4 colors. I ...
3
votes
1answer
188 views

color gradient (or color ramp) in Arcgis and Qgis

I am currently working on my thesis and I would like to ask you: does anybody know the mathematical formula that calculates the color gradient in Arcgis and Qgis? In other words, which mathematical ...
3
votes
1answer
103 views

Labels with white (or other color) background

I tried to give my labels somekind of box and a backgroundcolor (or boxcolor) in QGIS, but i couldnt find the right option. My labels are not readable because my layers are too dark. I found offset ...
1
vote
2answers
88 views

Is it possible to import SAGA colour styles in QGIS?

iam still using QGIS and SAGA independently in my productive use (despite the excellent SEXTANTE toolbox, which is sometimes a little buggy). SAGA has some very nice default styles and i am wondering ...
2
votes
2answers
431 views

How to create a map with states by attribute value?

I'm using Qgis, but I am quite familiar with R and python. So I could use any of these. I want a map of mexico but want to color the stats according to a certain variable. It goes from 0 to 100. So ...
0
votes
1answer
102 views

Coloring pixels based on values

I have an image where pixel values are integers, they go from 0 to 6 and I also have some 999. I want the value 999 to be transparent, which I could achieve by myself. I would like values 0 to 6 to be ...
2
votes
1answer
141 views

How can I apply correct colours to an elevation raster?

I have a problem to display elevation data with pseudocolours. The channel 1 is from -3.40282e+38 to 149.717 . A colleague used 1.7. and it looks like it should (from blue to Red) when I use QGis 1.8 ...
2
votes
2answers
285 views

How do I use ranges for raster colour map in QGIS

I have a raster layer in GeoTIFF format, with continuous data values between -1 and +1. For the colour map, I would like... >0 to be green = 0 to be grey <0 to -0.25 to be pink <-0.25 to ...
2
votes
2answers
849 views

Looking for a colormap for SRTM like OCM Landscape

In Quantum GIS there's an OpenLayers plugin. I would very much like to use the same colormap/scheme/theme used in the OCM Landscape layer and apply it to SRTM image I have. I checked the the open ...
6
votes
2answers
1k views

How to change DEM's gradient colour?

I'm a newbie about GIS. I'm from Italy and I've got a *.tif file of my region. I've loaded it has raster but I have a question: The dem has a gradient colour magenta. How change this colour to ...
1
vote
1answer
133 views

hypsometric colors alà IMHOF, SYDOW or PEUCKNER

I need a hypsometric color-map to add it to my multishade-modell. (High Mountain between 800 and 4000m) There are a lot of differend typs explained in IMHOFS "Cartographic Relief Presentation". I want ...
2
votes
2answers
214 views

How do I create a negative to positive value raster with neutral 0?

I have a raster layer with a band with values from -137 to 9229. I want to create a color scheme showing how far from 0 the positive numbers are in one color, and how far from zero the negative ...
2
votes
2answers
148 views

How to modifiy how selection highlights are displayed?

I have got a layer of points that are showed with a litlle symbol. When I select one, a red square comes around it. The problem is that this points are inside other layers (polygons) and some of them ...
2
votes
2answers
927 views

How to give multiple colors to features within a single shapefile?

I want to give multiple colors to different features within a shapefile based on attribute values , is this possible in QGIS ? If yes what is the procedure ? Is there a way to provide color by means ...