Let me explain this question as well as I can because I'm told that poorly written questions tend not to get replies.
I have created a distance raster from a point. The cellsize is small (5m) and the extent is large (50km) so we should get a nice continuous field of values in the distance raster.
To symbolise it the only option is Stretched. Great. So I choose a nice white to black stretched ramp. Assuming that we've got at least 8bits (and I was hoping more) of data for our monochrome scale I was hoping to have a nice gradation. But not so.
Check out the attached jpg. Look at the RGB values in photoshop: they jump in values of two or three. I would have hoped to get a nice smooth gradation but instead the stretched symbology results in an ugly discretization of my data. Why I can not have grey values from 0 to 256? It looks like there's only about 100 gradations. That ain't right. It looks ugly as you'll see.
How do I get a smoother set of grey values? Thanks
I have created a distance raster from a point. The cellsize is small (5m) and the extent is large (50km) so we should get a nice continuous field of values in the distance raster.
To symbolise it the only option is Stretched. Great. So I choose a nice white to black stretched ramp. Assuming that we've got at least 8bits (and I was hoping more) of data for our monochrome scale I was hoping to have a nice gradation. But not so.
Check out the attached jpg. Look at the RGB values in photoshop: they jump in values of two or three. I would have hoped to get a nice smooth gradation but instead the stretched symbology results in an ugly discretization of my data. Why I can not have grey values from 0 to 256? It looks like there's only about 100 gradations. That ain't right. It looks ugly as you'll see.
How do I get a smoother set of grey values? Thanks
I created a distance layer, symbolized it from white to black, did a screen shot and analysed the results. It's clear from looking at the RGB values in photoshop that values change quite abruptly, say from 255 to 252 with no grades in between.
For a basic 8 bit per channel graphic you'd expect 256 levels of grey.
Guess how many ArcGIS renders? 186 levels! I analysed the screenshot to see how many unique grey values there are, and the answer is 186. Which is somewhere between 7 and 8 bits.
I find that really shocking. Therefore I'm inclined to believe I must have a wrong setting. All the other GI products I've tried yield smooth gradations using full 8 bits. How do I get ArcGIS to give me 8 bits (or preferably more, even though I wouldn't see the difference on screen) of data? I have to say I'm quite disappointed, so I'm hoping someone can tell me how to fix this crazy situation. Thanks in advance, I do hope someone can help.