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Same scale for multiple rasters' symbology of a "Stretched" style

September 09 2011 | 14 comments
Categories: Symbology

I have four rasters that all have different scales associated with the min/max values. I need to represent all of these rasters with the same color ramp applied to the same scale value for all four rasters so that similarities and dissimilarities can be noticed between the four rasters easily. Is it possible to do this as a "Stretched" symbology where I key in the max/min values for the color ramp to be applied to?

Mapping Center Answer:

The better way to do this is to use a color map file. In that file you would define the colors as RGB values and you would define the values associated with each color.  That way, for all of the rasters, the same values will have the same colors. Here is a link to the online help topic about how to create a color map file.

Not going going to work that well: posted by Andrew Orr on Sep 9 2011 10:36AM
Not quite the answer I had hoped for. The problem is that the raster is a floating point format so the set of values is seemingly infinite. Additionally, it would take oodles of time to generate the color codes for a color ramp-appearance on this infinite dataset. Not exactly something I can do. :-( Any additional methods you can discuss, please?
Minimum-Maximum stretch type posted by Aileen Buckley on Sep 9 2011 11:20AM
The next best alternative is to use the Minimum-Maximum stretch type and edit the high/low values to be the same for the display of all the rasters.
Thanks! :) posted by Andrew Orr on Sep 9 2011 11:34AM
Thanks Aileen! That worked great! Somehow I totally missed seeing that min/max option when I was reviewing the list. My bad!

BTW, not sure if you remember me but hello from a former UoR student. We had dinner almost exactly a year ago with Tony Turner after he gave his agent-based modeling colloquium. :) -Andy C18.
Glad that worked! posted by Aileen Buckley on Sep 9 2011 11:42AM
Glad that option worked for you! Nice to hear from you!
Same colour ramp for Different raster posted by Rahul Roy on Mar 5 2013 3:51AM
i have 12 different month rainfall data with the min/max value.i need to represent all of these data with the same colour ramp . my max value is 700 and min value is colour ramp scale should 0,100,200,300,400,500,600,700 like this .i want to use same scale color ramp in each different raster for plot the data ...
i have IDW techniques applied raster Image in different month ...kindly any one suggest me how to do it ????
Use a colormap file posted by Aileen Buckley on Mar 5 2013 9:45AM
This is an instance in which it would be best to use a colormap file -- with a colormap file, you assign specific colors to specific values or ranges of values (for example, in your case, 100-199, 200-299, 300-399, e5tc...) Then when you use that colormap with any of the rasters, the same colors will be assigned to the same values or ranges of values.
ReSubmit: Same Color Ramp For Different Value Of r posted by Rahul Roy on Mar 5 2013 9:38PM
Thank you sir ....actually i have 12 month Rainfall image ..accordingly month rainfall will increase and decrease..i want use one common color ramp scale accordingly my highest lowest value in the all image ..suppose my color ramp scale will increase yellow to red than yellow color represent low value ,yellow & red mixing color show moderate value and only red color show the high value .
for example when i plot january month image,my color ramp scale will fixed (i took scale , from 0 to 700,scale interval 100),in my data January month highest rainfall 70 and lowest rainfall per as my clor ramp show 0-70 yellow color .so my image color should be yellow thats i want ...but i can't ...plz suggest me mail id
Still need to use a colormap file posted by Aileen Buckley on Mar 6 2013 9:06AM
Yes, I think I understand. For what you want to do, you still need to use a colormap file. Here is a link to a map we made that does pretty much what you are talking about although the theme of this map is temperature rather than rainfall.

Download and unzip the file, then open it in PowerPoint and play the presentation.

You will see that the same legend is used for all time periods. The colormap file we used is also displayed in the legent -- the legend shows the full range of temperature values for all time periods and the associated colors in the color map file. That one colormap file was applied to each time period. Therefore, whatever the range of temperatures was in the time period, it used that range of colors in the colormap file, and if temperatures were out of the range for that time period, they were not used.

I think this is pretty much the same thing that you want to do -- so the answer is the same -- use a colormap file that contains the full range of values and apply it to each time period. Only those colors that are in the range for the time period will be used.
ReSubmit: Same Color Ramp For Different Value Of r posted by Rahul Roy on Mar 7 2013 3:53AM
Thank you sir ..i have done this work ...but image color is not coming continuously,its like break ...
For example when we do Interpolation techniques than image color should be come continuously....i want like this type of color in my image to do it ??....plz suggest me
Snooth color progression in a colormap file posted by Aileen Buckley on Mar 7 2013 12:47PM
To create a smooth color progression in the color map file, you need to include the values between the breaks as well (or at least a enough of the values between the breaks that the progression appears smoother). For the values between the breaks, you can linearly interpolate the values for the RGB color definition. For example, imagine you have one color for the value 0 and another for the value 10:

0 255 255 0
10 0 255 255

Then you can linearly interpolate the 9 values between the colors 255,255,0 and 0,255,255:

0 255 125 0
1 230 112 25
2 204 100 51
3 178 87 76
4 153 75 102
5 127 62 127
6 102 50 153
7 76 37 178
8 51 25 204
9 25 12 230
10 0 0 255

To get these numbers, take the range of one of the R, G, or B values (e.g., 0 to 255 – the range is 255), divide by the number of values in the range (in this case, dividing by 10 gives you 25.5), then add that value to the lowest number and use that as the next number in the color definition (in this case 25). Then add the value again to get the next color definition (25.5 + 25.5 = 51). And so on. Do this for all the R, G, and B values.

Note that you cannot use anything except whole numbers in the color definitions, so either round up or down – it won’t make much difference in the color you see whether you round up or down.

I hope this helps!
Smooth color progression in a colormap file - easy posted by Sanjay Wadhwa on Apr 23 2013 2:39PM
To create a smooth color progression in symbology if you have 9 classes and you have chosen a colour for first and last class. Then select these two rows and rightclick -> 'ramp colours' and ArcGIS interpolates intermediate colours. If you want a specific colour colour for the middle class, set the colour for that class. Then select three rows top middle and bottom using Ctrl key and right click on any selcted class and choose 'ramp colours', instead of manually interpolating RGB values.
Export to Colormap posted by Aileen Buckley on May 4 2013 1:38PM
Once you have created this set of ramped colors, you can click the Colormap button and click Export a Colormap. This will save your symbology for future use with this or other rasters.
how to create same scale for multiple rater(32 bit posted by shouvik jha on Mar 12 2014 9:55PM
I have five IDW interpolation output raster maps that all have different scales associated with the min/max values. That all rater have 32 bit floating value. i want to make same scale for multiple raster. but problem is when i am going to create .clr file that time my colormap buttom is showing disable...what should i do. kindly suggest me ...
Can't use color maps with floating point data posted by Aileen Buckley on Mar 19 2014 12:09PM
Color maps are not supported for floating point data types. You can either convert the data or you can try using the classified renderer instead.

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