sql - How do I change the radius of a circle in PostgreSQL? -



sql - How do I change the radius of a circle in PostgreSQL? -

(using postgresql 9.1, without gis stuff installed)

assuming i've got box (which should square):

> select box '((0, 0), (1,1))' "(1,1),(0,0)"

i can circle fits within square:

> select circle (box '((0, 0), (1,1))') "<(0.5,0.5),0.707106781186548>"

and bit of messing around can bigger circle:

> select circle(center(circle(box '((0, 0), (1,1))')), radius(circle(box '((0, 0), (1,1))')) * 2) "<(0.5,0.5),1.4142135623731>"

but doing prepared statement means passing square twice:

"select circle(center(circle(?)), radius(circle(?)) * 2)

which isn't deal breaker, sense there should 'better' way of doing it.

is there easier/better way of resizing circle? specifically, want circle center @ center of box, , radius equal half diagonal length of box.

(if helps, i'm using "contained in or on" ('<@') operator set of points within area)

thanks.

i build statement using sql 'with' command. want of form:

with bxx (select center(bx) cb, length(diagonal(bx)) lb (select box('((0,0),(1,1))') bx) bun) select circle(cb, lb) bxx;

the clause generates table used in next sql (select in case) statement.

what here build table containing column box center , 1 length of diagonal. subquery in 'with' clause establishes box column (bx).

sql requires subquery named, hence 'as bun' -- unused.

this construction makes easier fiddle center , length parameters variations of problem.

i should point out in problem statement, first circle create outside box (center in center, radius half diagonal -- meaning box inscribed in circle). circle within box, want utilize radius length of half length of sides of square, not diagonal.

sql postgresql geometry

Comments

Post a Comment

Popular posts from this blog

c - Compilation of a code: unkown type name string -

c - Compilation of a code: unkown type name string - i have next lines of code compiler says following: "unknown type name 'string'" both in declaration , definition of function. can tell me what's wrong? thanks. #include <stdio.h> #include <stdlib.h> #include <string.h> void frecognizeclient(string *actualclient) there no string type in c. need utilize array so: char array[10]; then can pass in function: void frecognizeclient(char *actualclient); c arrays string compilation
Read more

java - Bypassing "final local variable defined in an enclosing type" -

java - Bypassing "final local variable defined in an enclosing type" - i'm writing programme , i'm getting "the final local variable asd cannot assigned, since it's defined in enclosing type". i provide illustration not code produces error aswell. have arraylist utilize later (if define within button can't utilize later on), outside of button, pressing button should give values arraylist. in illustration "create new arraylist" cause same problem. button btn = new button("asd"); final arraylist asd = new arraylist(); btn.setonaction(new eventhandler<actionevent>() { public void handle(final actionevent event) { asd = new arraylist(); //here's error.. } }); clear arraylist , add together values. java javafx
Read more

json - Hibernate and Jackson (java.lang.IllegalStateException: Cannot call sendError() after the response has been committed) -

json - Hibernate and Jackson (java.lang.IllegalStateException: Cannot call sendError() after the response has been committed) - hello have problem hibernate , jackson. have 2 pojos @entity @table(name = "users") public class user implements serializable { static final long serialversionuid = 4235637833262722256l; @id @generatedvalue private int id; @column(name = "creation_date") private date creationdate; @column(name = "first_name") private string firstname; @column(name = "last_name") private string lastname; @version @column(name = "version") private int version; @column(name = "e_mail") private string email; @column(name = "enabled") private boolean enabled; @column(name = "login") private string login; @column(name = "password") private string password; @jsonmanagedreference("role") @onetomany(mappedby = "user", cascade = cascadetype.all,fetch = fetchtyp...
Read more