Re: Help creating "corridors"

On 2/6/2025 11:30 AM, Luca Bertoncello wrote:
>> To create a true corridor you probably should buffer the line string too
>>   and add an altitude  something like below which would expand the
>> linestring to 500 meter area and then maybe you add a upper altitude /
>> lower altitude as separate columns for restrictions, but I think even
>> the altitude restrictions change across the corridor so even this might
>> not be enough to assume it’s constant across the corridor
> As I said, I don't need the altitude, but buffering could be a good
> idea, since the tables are huge...

Luca,

Buffering isn't unlikely to help performance while manipulating a large 
collection of points.  Which is my interpretation of your intent in the 
statement above.

Nobody really asked you what you meant by "corridor".  Were your looking 
to display area (polygon) or path (linestring) information?  Buffering 
turns a point or linestring into a polygon, allowing you to identify an 
"area".

You seem to have a grasp of how you want to acquire points for the end 
points and "along" your corridors.  I am going to point out that Regina 
implied (but didn't state), that an "order" is required on your points 
to get a sane linestring to represent traveling from point A to point B 
along a collection of points. (Simon's reference also uses an "order", 
just a different type)

But, if you won't have an "order" on your distinct points to help with 
drawing a linestring from Point A to Point B, you can probably build a 
polygon from the points.  Buffering points and union'ing them to a 
(multi)polygon might allow you to build your "corridors".  Doing that 
would best be done on a corridor by corridor basis (using some other 
attribute on your points) because I suspect you have multiple corridors 
going out from airports and "just" buffering "all" points will result in 
nothing particularly useful.

Roxanne