DPI vs. PPI - What's the difference?

[RPMiller]

Excellent post RobA! Thanks for the additional information. Especially regarding Xara, and the vector information.

Yea, the vector VTT idea is routinely brought up. I think the reason there aren't any (that I know of) is because the programming is a lot more complex than just dropping in a raster image. The nice thing is that most folks typically don't zoom in more than 200%, with exceptions of course of what they are looking at at the time. That would be cool to be able to zoom in all the way to read the page of a book lying open on the table. MapTool has sort of taken care of that though in that you can now add an associated image to the object so that if a player hovers their mouse over the object a window pops up with an image.

[RobA]

I think the reason there aren't any (that I know of) is because the programming is a lot more complex

Hopefully that will change, as the next version of SVG standard will have some adaptive Level-of-Detail definitions. This web site describes the current proposal - and it looks pretty nifty.

-Rob A>

[RPMiller]

Nice! Some of those same algorithms are being used as guidelines in some of the new gigapixel images as well. Yes, I said gigapixel. If you haven't seen some of the new gigapixel images they are worth googling.

[Gamerprinter]

The issue with my exterior map is that I scaled it at 1" = 20 feet and it measures 54" x 43", thus the true measure is 1080 feet x 860 feet.

Even if I forget about DPI and stick with pixels only. At 200 pixels every 5 feet, that's 43,200 pixels wide by 34,400 pixels - Xara won't let me export something at that size. In fact Photoshop won't let me create or open an image that is larger than 30,000 x 30,000 pixels.

This means I need to slice my image into multiple pieces, probably in quarters.

I was able to force the dpi down to 50 in Photoshop, but it would still not let me create more than 30,000 pixels in any dimension.

Lastly Kalmarjan describes a maximum normal map size at no large than 100 x 100 feet at 4000 x 4000 pixels. My map is almost 10 times that in dimension. It might be best for me to cut this image into 10 separate maps.

Thoughts?

[RPMiller]

You must be using an older version of PS. CS3 doesn't have that size restriction.

Breaking it up into smaller pieces would certainly work, but it would be a little clumsy.

Regional maps in VTTs are not that small. In fact, one of the strengths of MapTool is that it practically has no maximum size. Realistically it does, but it depends on what is on it. That also is assuming that you are creating the map directly in MapTool instead of importing an external pic. Some of the tests we've done have been with maps that were a mile long and longer per side. As I suggested before, you should sign up at the various VTT forums and take a look at their capabilities and what others are doing if you are serious about getting into that market.

[Gamerprinter]

So I should download the newest version of GIMP, since I don't plan to upgrading PS anytime soon. The latest GIMP should be like the newer versions of PS in this respect.

Yeah, I'm using PS 5.5, quite old. I got disgusted with some of the features to CS and never upgraded because of them.

Still Xara won't export the full map at that pixel resolution. Xara still looks at it in DPI and says it is limited by 9 feet in any direction (!)

[Gamerprinter]

Knowing that I have an older version of PS with a limitation of 30,000 pixels in every dimension, first I cropped the original exterior map to just the compound the octogonal walls and everything within and a few outside trees.

I opened and rescaled the map in PS without resampling and ended up with a map file at 200 pixels = 5 feet. Conversely, the non-essential DPI data is 7.25 dots per inch. Still the file is 25.5 MB in size and in PNG format.

I feel this is still too large, however, I can upload into my FTP account if anyone (RP specifically) wants to download it for their own uses.

Once I get an upgraded version of GIMP I'll probably be able to do the entire map, of course the file size would still get much larger.

Thoughts?