New layers from selected boundaries

[haza100]

Hi,


New here, and was wondering if someone could help me out:


Basically I have several maps which have had black lines drawn on them - I would like to separate the different 'sections' of each map based on the boundaries.
I am able to select the black line with the magic wand tool - however this isn't proving much use


Here is an image to further demonstrate what I'm trying to achieve:




Many thanks

Harry

 

[hawkeye]

The pen tool would be the best way to make an accurate selection.

 

[ALB68]

You can also use the Quick Select tool. Select inside the boundary, then Select/Modify/ Expand (3 pixels), Ctrl J and you got it. Don't feather the mask or you'll have to clean it up a little.

(I'm assuming your pointing to the larger section, otherwise if it's the small one, the pen would be better)

 

[dv8_fx]

As mentioned... Pen tool is the best.

But if you're not comfortable with the PenTool, you can take the lasso to make a close cut selection of a section, copy to new layer and erase the outlying parts using a hard tip eraser tool. Repeat on each area......

To ease selection with Lasso tool, Hold down ALT and click your selection around the area.. release ALT to complete the selection.

For a straight direction erase, click your first erase point, hold down SHIFT and click second point... click 3rd point... so on so forth.

 

[ibclare]

Well, it depends too how crisp you want those lines. Another option would be to use a hard brush or the pencil, click where you want to start, go to the end of a straight line before it turns, hold down shift and click again. Repeat. Do this on a layer above your map.

The wand doesn't work bad if you click outside the line to isolate it, then you can refine the edge, choose white background, smooth it a small amount and narrow or widen it, like ALB suggested. Then you can fill the new selection with black, on a new layer, and this might work.

But if you want really crisp edges, the pen tool will work best. Since you have essentially straight lines, all you have to do is make your line down the center of the map guideline, then activate the pen tool path and go to edit>stroke and choose the pixel width you need. This is similar to the first method I described. Again make all these marks and strokes on separate layers.

Try the assortment we've suggested and see what works best for you.

 

[rev]

A Very Quick but Accurate method

1. Add a "Brightness/Contrast" adjustment layer and set both values to maximum at 150.

2. With the Brightness/Contrast layer selected, use Magic Wand to select the inside of one of the areas within the black boundary (feather 5, contiguous turned on) * If a few unwanted specks are excluded inside the selection, use the lasso tool with Shift key to Add the excluded specks into the selection

3. With the interior of the area bounded by the black boundary selected (marching ants appear), SELECT the ORIGINAL image layer and COPY/PASTE to generate a new layer with the selected area

Done. (If you need more than one area, repeat 1-3 with new area selected each time with Magic Wand)

* Remember to select the Brightness/Contrast adjustment layer before using Magic Wand tool and to select the original image layer to COPY/Paste (if you forget, weird results will be made: eg. partial selection etc)

* If you want to add the black boundary, select the pasted layer and double click the layer to bring out the Layer Style menu > select Stroke option: Size 1 or 2, Position: Center (If you want more polished/accurate edges, one could use "Refine Edges" to remove unwanted dots on edges BEFORE applying the Stroke)

* If all the maps are essentially similar, you can simply drag the Adjustment layer to new images to save time

* One example was attached on this reply (with Stroke Size 2)
Good luck

 

[rev]

Re: A Very Quick but Accurate method

Sorry the title should have been "A very quick and FAIRLY accurate method". I still cannot edit my posts, yet
* Also, I just found out setting the Magic Wand's Feather to 10, and Stroke Size 1 (Center) yielded significantly more accurate stroke.

 

[ibclare]

Excellent idea! It should have occurred to one of us. Oh wait, it did. It occurred to you Rev. So I tried a levels adjustment which gives just a slightly darker line. Then I wondered if a threshold would work and it did also. Great thinking Rev.

Hopefully, the OP is still working on this and will see it.I don't even think the magic wand will be necessary, just a bit of lasso as you suggested, then cut the lines into their appropriate sections. If I understand the need that is.