transparent color
djamel
Global Mapper User
in Raster Data
Good afternoon
when i try to choose a transparent color for a raster layer I dont have the box with the title : " transparent color"
and when I choose a color from the color palet I D'ONT HAVE A RESULT. Any help please ; I 'm using GM v 17.1 thanks.
when i try to choose a transparent color for a raster layer I dont have the box with the title : " transparent color"
and when I choose a color from the color palet I D'ONT HAVE A RESULT. Any help please ; I 'm using GM v 17.1 thanks.
Answers
-
Hello,
What version of Global Mapper are you using? What is your workflow when you choose a transparent color, i.e., what steps are you performing in Global Mapper?
Cheers,
Bob -
Good Morning
I'm using GM V17.1. After opening a raster I have done these steps:
control center , option ,display tab , transparency , set transparent color ,I choose a color (indicate RGB values) , apply ,no result
thank you for your help. -
djamel said:I'm using GM V17.1. After opening a raster I have done these steps:
control center , option ,display tab , transparency , set transparent color ,I choose a color (indicate RGB values) , apply ,no result
thank you for your help.
Unfortunately, we don't currently have a way to pick the RGB values from the image. There is an open feature request to be able to do that, but it hasn't been implemented yet. In the meantime, if you know the RGB values you want to use, you can type them into the Color dialog, as you are doing. Then, on the Display window, move the slider under "How Similar Must Colors be to Make Transparent?". If you move the slider towards "Fuzzy", you will get more pixels marked as transparent.
If you are not sure what RGB values to use, choose the Feature Information tool and click on your raster image. The Pixel Information screen will be displayed with RGB info about the pixel you have clicked on.
Cheers,
Bob -
I think I might be the person that originally suggested/requested that the transparency function for colors have a slider, instead of a fixed, built-in default value. I was trying to clean-up some lossy .jpg imagery with a lot of noise.If I remember, the old default value was 17, so it's possible that you may have to get at least that 'fuzzy' to start seeing an effect, rather than at 0. Some imagery (like .jpg) has so many different RGB colors that picking one of them for transparency from what seems to be a single color to the eye may not have the desired effect. Getting more 'fuzzy' can help, but almost always, pixels then start dropping out of areas that you don't want to be transparent. Trying to make water transparent this way on satellite or aerial imagery is a classic example. It seems to all be a similar color, but it's not really, and the land areas will have similar pixels that will start disappearing. Only a mask, or crop will work well.Sometimes you can use another program (like free Irfanview), to change several/many different pixel colors to the same single RGB value, and achieve some additional transparency effect in that way.With pallete based imagery, you can choose more than one color to make transparent by using 'Control' or 'Shift' to multiple select. With non-pallete imagery you can also make multiple colors transparent, but only by using a simple script. In the script, you can specify more than one RGB combination for your transparency color. They will all have the same 'fuzziness' though; i.e. you can't specify that seperately.Hope those couple of tidbits might help anyone using this feature in GM.Mark
-
it works now , thanks
Categories
- 12.7K All Categories
- 5.6K Features Discussion
- 342 Downloading Imagery
- 1.3K Elevation Data
- 380 Georeferencing Imagery Discussion
- 628 GM Script Language
- 53 User Scripts
- 113 GPS Features
- 414 Projection Questions
- 819 Raster Data
- 1.3K Vector Data
- 6.6K Support
- 177 Announcement and News
- 908 Bug Report
- 558 SDK
- 1.2K Suggestion Box
- 3.7K Technical Support
- 562 Other Discussion
- 129 GIS Data Sources
- 27 Global Mapper Showcase
- 233 How I use Global Mapper
- 107 Global Mapper Forum Website