16 replies to this topic

[Helo]

Hi

I'm making a series of maps in ArcGIS. One of the layers is a polygon shapefile laid out in a grid pattern. I'm exporting as an AI file to do the cleanup and ultimately saving the map as a PDF.

The problem I'm having is that the boundaries between the shapes in the gridded shapefile are showing up. They aren't visible in the printed version and there are no borders. But in Illustrator and as a PDF the boundaries show up lightly as artifacts. The best way I can figure to get rid of this is to somehow merge all the cells in that layer. I don't know what else (if anything) can be done.

I've attached a sample of what I'm talking about. The coverage shows concentrating solar power in Arizona but there isn't supposed to be a gridded appearance to it.

Does anyone have any suggestions?

Thanks so much,
Helo

Attached Files

•  CSP_low_Arizona.pdf   105.63K   98 downloads

[Martin Gamache]

1. You can add cells together of the same color using the pathfinder tool.
2. You might try to rasterize the layer containing the cells for the web distributed pdf.

[pfyfield]

You could dissolve the shapefile based on the attribute you're mapping in Arc, or you can select by fill color and merge in Illustrator.
Occasionally ArcMap will export fills and strokes separately, so your fill may show no stroke. Can you select the outline? Then you could select by stroke color and delete.

By either dissolving or merging you eliminate all the interior linework, which has the added benefit of reducing file size, if that's a concern.

[MapMedia]

Original data looks pretty sloppy. Was it converted from raster or CAD to polygons?
You might just apply a stroke of same fill color in Illy to bridge the gap.

[peanut]

Vector data comes from ArcMap into Illustrator better if you export with the resolution set to multiples of 72. This eliminates rounding errors in the export. This may or may not help you with the problem you experiencing.

Rich

[frax]

Dissolve (Arc) or merge (pathfinder)!!! This will also reduce the number of paths in the file, which decreases the file size.

(No, Derek did not make me say the above!)

[Helo]

Okay, well here's the issue I have with Illustrator. There doesn't seem to be any way to turn multiple objects into one single objects. Yeah there are lots of ways to make it LOOK like that, but no matter how many times I try to use the pathfinder I STILL end up with a compound object.

Why, pray tell, is it so hard to turn several overlapping polygons into ONE SINGLE SHAPE? No outline trickery, no compound shapes, just one solid inseparable simple polygon. Has this simple feature been completely abandoned?

[Helo]

Original data looks pretty sloppy. Was it converted from raster or CAD to polygons?
You might just apply a stroke of same fill color in Illy to bridge the gap.

Uh no the data isn't sloppy. It's 10 meter resolution and it was not converted from raster or CAD, and a stroke of the same fill wouldn't work because all the polygons are not the same color.

[Hans van der Maarel]

Okay, well here's the issue I have with Illustrator. There doesn't seem to be any way to turn multiple objects into one single objects. Yeah there are lots of ways to make it LOOK like that, but no matter how many times I try to use the pathfinder I STILL end up with a compound object.

Why, pray tell, is it so hard to turn several overlapping polygons into ONE SINGLE SHAPE? No outline trickery, no compound shapes, just one solid inseparable simple polygon. Has this simple feature been completely abandoned?

IMHO, this is not something for Illustrator to solve, specifically because it lacks this feature. As has been suggested before, try and combine (dissolve) those polygons in Arc first.

[Jimbo]

Okay, well here's the issue I have with Illustrator. There doesn't seem to be any way to turn multiple objects into one single objects. Yeah there are lots of ways to make it LOOK like that, but no matter how many times I try to use the pathfinder I STILL end up with a compound object.

Why, pray tell, is it so hard to turn several overlapping polygons into ONE SINGLE SHAPE? No outline trickery, no compound shapes, just one solid inseparable simple polygon. Has this simple feature been completely abandoned?

IMHO, this is not something for Illustrator to solve, specifically because it lacks this feature. As has been suggested before, try and combine (dissolve) those polygons in Arc first.

In CorelDraw you can select multiple objects & combine them as one but if there's any gaps you have alot of manual topological editing ahead of you. With Arc I find when you bring the eps file into a graphics package you run into a problem with the size of the package, it causes the graphics package to run rather slowly. For example I have in my portolio a huge file with an upside down perspective of North America, the printer wouldn't even accept it because of the file size. The data was geoprocessed in ArcView using merge, dissolve, & intercept.

[frax]

Hans and Helo - if the paths are close enough, you should be able to merge them using the pathfinder tools, not to a compound path - but it merges it into a new path, without the internal boundaries.

Check the Illy help file for more info

[Hans van der Maarel]

Hans and Helo - if the paths are close enough, you should be able to merge them using the pathfinder tools, not to a compound path - but it merges it into a new path, without the internal boundaries.

True, but I'm guessing there's some mathematical rounding errors coming into play here, which could be circumvented by doing the merging in Arc.

[frax]

True, but I'm guessing there's some mathematical rounding errors coming into play here, which could be circumvented by doing the merging in Arc.

Yup, and if you have simplified them, you might not be able to do it. Simplify is dangerous in that respect, no turning back (I wouldn't mind if it was a filter instead).

[Helo]

Okay guys

I was working on two separate but related problems at the same time.

To solve the issue of the lines between the resource grid cells, I just put a solid layer behind it that was colored to match the middlemost color of the grid (ie. not the darkest, not the lightest, but a shade in between) and it somehow managed to take all the lines out. I'm making 500 of these maps, different versions for all 50 states, and the data is much to complex and cumbersome to try merging polygons in Arc. By trial and error I figured out a workaround that'll have to do.

The other issue was clipping. For some reason, when I export some state outlines from Arc and open them in Illustrator, the states are converted into compound objects, and these objects simply will not clip the data correctly. Since you can't make a clipping mask out of a compound object, and you can't make a compound object into a single object I was stuck. (I'm still in utter disbelief that Illustrator CS2 can't do these extremely basic things.) I did finally figure out, no thanks at all to the help menu, that using "crop" from the pathfinder will achieve what I need, but only after exporting the state as a solid shape with no boundaries as PDF from Arc, opening in Illustrator, rasterizing, using Live Trace to convert it back to a vector with considerably fewer components, using Pathfinder to "add" the state back into (sort of) one shape, then using the "crop" function to clip the solar resource to the state. After days of trial and error this is the first thing I've found that will work.

I'm really just flabbergasted at how difficult this seemingly simple operation turned out to be. Most states export as a single shape from Arc. I don't know why a few won't (though I suspect it has something to do with extremely complex shorelines because that seems to be the common denominator). I'm quite accustomed to Arc's shortcomings but I guess I expected a lot more from Illustrator.

Anyway I wanted to thank all who responded and offered suggestions. This was my first experience posting on CartoTalk.

[frax]

I think you might get compound shapes when there are islands, either in lakes or off the coast.

On your workflow, I think you just need to experiment and see what works and what doesn't - I don't have any major problem with Arc.

When you mention boundaries, by the way - I never style polygons with both color and stroke in Arc before exporting to Illy.