Polyline vs Polygon

[Mac]

People are going to get tired of me, however have no other place to find out this information.

Using FSX KML

Firstly let me explain the method I have been using for the canal and a river. There is no exclude water as it is all on land.

Using a polyline (path), I will draw up the west side of the canal or river.

I will then save this as my hydro poly and the west shoreline of the canal or river.

Then back to the original polyline saved as the hydro poly. Cross over the canal or river and draw down the opposite or east side of the canal or river and save.

I also save this as the east shoreline. Using the east shoreline polyline I delete the west side of the canal or river and save.

I now have three files, west shoreline, east shoreline and hydro polyline.

I now will go to the hydo poly and join the ends making it into a polygon.

Now the problem:

Adding islands. When I did this in the canal I was able to insert islands into the hydro poly and they all showed with no problem.

However, when I used the same system in the river the island will not show.
I have to go back and use the polygon rather than the polyline.

For some reason when in a river the polyline is not recognized by the PolygonHole, while in the canal it is.

Maybe this system is not the proper way to do things, but it does make it so I am not having to trace over other polygon lines to get shorelines.

It seems that a polyline joined to make a polygon is not the same as a drawn polygon, even though it acts like one in GE.

Is this a problem with FSX KML or with the sim itself? I'm afraid it is a way over my head.

Sorry this is so long. Should have everyone else confused now.

[radivil]

Quick answer: you can't put a hole in a line. I mean, how can that even work?

I hate to do this but I was just about to head out the door when I thought "i'll check one last thing before I got." When I get back, I will type up everything you need to know to do this easily. Mainly, I post to tell you there is hope.

[BJamieson]

If the main thing you're after is shorelines for your 'ponds'.

What I did was

Create a folder called ponds - it gets the tag of hydro-poly-water (or whatever)... Inside it there are polygons. EG Polygon called 'west arm' (and since the folder has the tag, all these polygons are left un-tagged).

So, 'west arm' is responsible for producing the 'water effect' for west arm canal...

Flying along, I notice that there's not much of a shoreline going on there...

Solution:

Second folder (after the first one...) with a tag of thingumy-shoreline-perenial (you can tell Im not at home on my development machine here )

All you need to do is copy the polygon responsible for 'west arm' and bingo, you now get the shorelines - EVEN though you are tagging a polygon, with a line type of attribute ?

Make sense ? or clear as mud ???

B

[Mac]

To Radivil:
Would appreciate the help.

I do realize about not being able to put a hole in a line.

What really confuses me is when I take the line and make it into a polygon and cannot put a hole in it.

I guess I shouldn't say I can't as sometimes it will work and sometimes not.

Very confusing.


To BJamieson:
What I have been doing is using the line poly and using a shoreline tag. If I use a polygon for the shoreline and tag it with a shoreline tage I get shorelines showing out in the water where there is no shore.

I have attached the KML. If either of you have time perhaps you could have a look. I am afraid I am not very good at explaining the problems when I know so little.


In the KML the shorelines on the canal were originally line polys which were connected and made into polygons and I was able to insert some islands.

On the river where the two islands are that would not work and I had to trace a polygon over the shorelines to get the islands to show.

[radivil]

Ok, I looked at your KML and I see that you do things a little differently than I would myself (and what I would have suggested that you do). Normally I don't draw separate lines and polygons for shorelines. I just copy and paste the water ones and reuse those for shorelines (with some editing in notepad).

Which islands are they that cause the trouble? Are they the two on this "Somass River?" I know literally nothing about Vancouver Island, so this is a new place name to me.

I've never seen someone use the folder's properties to apply a tag to all the polygons in that folder before. Does that work? I'd never tried it but now I'd sure like to. I have a LOT of islands in my project and a lot of shorelines.

[Mac]

Here are a couple of facts about Vancouver Island which is on the west coast of Canada.

VANCOUVER ISLAND FACTS
Size and Characteristics
· Length from North to South: 460 kilometres (286 miles) - almost the length of Ireland.
· Width from East to West: 50 - 80 kilometres (31 - 50 miles).
· Area: 31 284 square kilometres (12,076 square miles).
· Length of coastline: 3 440 kilometres (2,136 miles).
· Highest mountain: Mt. Golden Hinde at 2,195 metres (7,201 feet) - almost at the geographic center of Vancouver Island. Second highest is Elkhorn Mountain at 2,166 metres (7,106 feet) and then Mount Colonel Foster at 2,129 metres (6,985 feet).
· This is the largest island on the North American west coast.
· Total population;
o 2001 census approximately 664,451




The idea of the file folders came from "BJamieson" and seem to work well. Definately helps to keep things more organized.

I would have attached another KML which is further down the canal and opens out to the west coast of Vancouver Island on the Pacific Ocean but I think it is to big to get on here.

Yes, it was the two islands in the Somass River. They are ok now as I made a new polygon.



The main thing that confuses me is the darn polyline.

****In GE it seems that you can draw a polyline and then join the ends. It will then become a polygon.****

Where the problem arises is putting islands into the polygon that has been made from the polyline. Sometimes the PolygonHole recognizes the polygon and sometimes not.

The shorelines on the canal were done as polylines originally, then joined to make a polygon. No problem putting in the islands.

The Somass river would not work that way though and I had to use Polygon.


Like I said previousley, when you don't understand how something works it can make things difficult.

[BJamieson]

Hi folks,

Tagging the folders actually comes from the wiki manual (so I can't take credit for that one ).

It does work a dream for 'known' things like:

Folder Name - MyRivers
Folder Tag - Poly_Line_Rivers
Folder Contents - lots and lots of UNTAGGED polylines (these go from A to B, and not A - A ). These puppies will all appear as well, you know, rivers!

Folder Name - MyRoads
Folder Tag - Roads_Dirt_2_Lanes_Undivided_Median - ok you may want a seperate folder for the seperate road TYPES you can make - 2 lane, 4 lane etc...
Folder contents - lots and lots of UNTAGGED polylines. These puppies all become seen as, well, roads.


NOW tricky bit - and I found this bit out on my own :

Folder - My Ponds
Folder Tag - no tag applied...

Contents - two sub-folders:

SubFolder One
Folder - PondWater
Folder Tag - Hydro_Polygons_Generic_Lake_Perennial
Folder Contents - UNTAGGED polygons, eg a, b & c

SubFolder Two
Folder - PondShores
Folder Tag - Shorelines_Default
Folder Contents - copies of your UNTAGGED polygons, eg a, b & c

Now read that bit again carefully. The shoreLINES are made of polyGONS and not polyLINES. You don't need to change these puppies at all. So for every pond or lake polygon that you want to produce a shoreline for... JUST copy the polygon and paste it into your PondShores folder. WOT could be easier, eh ????


OK, so NOW you can see why I would like to be able to do 'multi tagging' of an individual polygon...

Polygon A
Tags might include:

PolygonHole
Hydro_Polygons_Generic_Lake_Perennial
Shorelines_Default

So that the one polygon can do several things... OK I know, that may not have been the best example, but you get the gist...

[Mac]

Good info!!


However, take a situation like the B.C. coastline.

The coastline is going to start at point 1 and end at point 2. If you use a polygon then one and two are going to be joined from the very beginning.

So if part of the polygon follows the coastline the other half will either be on shore or out in the water. If you tag the polygon as coastline the whole polygon will show coastline, not just the part that traces the coastline.

That is why I went with the polyline and joined it after saving it as coastline.

I'm probably missing something here, and if so appologize. Sometimes it takes a few knocks to get things into my head.

[BJamieson]

Nope, you are spot on.

That's why I was cheeky enough to keep saying ponds, and lakes , naughty, I know.

I understand exactly why you want to reuse your shorelines, to create polygon areas - it's the exact 'mirror reason' why I wanted to reuse my polygons, and stumbled on applying the line tag to the polygon.

The fact that you can even get a polyline to join to itself and 'become' a polygon AT ALL is awesome, (but by all accounts random ). I could only think of asking Mr S to add a widget to allow a line to become a gon and vice versa...

He has that slated for the next release - so everyone, please keep sending good karma and vibes and so on in his general direction...

[radivil]

Originally Posted by BJamieson

He has that slated for the next release - so everyone, please keep sending good karma and vibes and so on in his general direction...

Indeed, it was the only feature I ever suggested because it would be so very useful and I'm glad he chose to implement it. I'm really looking forward to getting back to work after its available.

That and the one where you can put a polygonhole in a folder and it looks in the parent folder for the polygon that will be holed. Whenever that one happens. If it happens.

[MatthewS]

Originally Posted by radivil

Indeed, it was the only feature I ever suggested because it would be so very useful and I'm glad he chose to implement it. I'm really looking forward to getting back to work after its available.

That and the one where you can put a polygonhole in a folder and it looks in the parent folder for the polygon that will be holed. Whenever that one happens. If it happens.

I've uploaded 1.09 with these features implemented. See this thread below
http://www.fsdeveloper.com/forum/showthread.php?t=5508

[radivil]

Originally Posted by MatthewS

I've uploaded 1.09 with these features implemented. See this thread below
http://www.fsdeveloper.com/forum/showthread.php?t=5508

Had some small islands waiting for the day that I could put them in a sub-directory of their own and find the big ocean polygon in the parent directory, plugged them in, and it worked perfectly without any trouble. Thank you for these new features.