GeoNames Forum

when i query (reverse geocoding) for a lat /long
i get a record (xml) back, with a house number odd or even.
how can you be sure taht the click on the map was right side or left side of the street ?

We find the nearest segment to the point you have clicked and then we figure out whether it is left or right. The dataset we are using gives us left and right streetnumbers for the start and end point of the segment. We will then interpolate the line number depending on left or right.

Would it help to have access to the information "left" or "right"?

Cheers

Marc

thak you for your reply again,
i dont undestand how do you figure the left or right side,
the sentence : "We will then interpolate the line number depending on left or right"
is not clear,i need to know how the interpolation is done,for my app. i need to verify it form 2 different sources.
if possible please tell me how is it done.

thanx,

htl.

A line has a beginning and an end. If you stand at the beginning and look towards the end then you have a left and a right side. The point you click is either left or right.

The interpolation is used to determine the house number since we only have the house numbers of the beginning and of the end of the line (four numbers, two on each end of the line)

Marc

Greeting from NZ, Thanks Marc for that info.
Some completchain is like

-----------------/
/

So you find the closest section in that chain and then do interpolation or portion of the left/right address range?

And also If you could shed some light on how to determine
the point is left or right for a given straight line in pgSQL&PostGIS
?

Btw, do you cope with house number which contains Hyphen for avenue?

Thanks for the generous project. Best luck from me for your future development.

G. LU

I've just found azimuth in PostGIS can help on determining location of the point against a line.
Correct me if I am wrong

Ow, I forget long lat theirselves are degree. HAha

Hi

We find the closest line segment with postgres and interpolate the address in this segment with java using the JTS Topology Suite for left/right.

Cheers

Marc

Marc, Thanks for the info!

how to Compute the house number at that point by interpolation between the known house numbers at each end of the road segment.?

Please give the formula ot general steps to do that.

finding house numebr from road segment (left or right) from fromhouse numebr to tohouse number.

is linear interpolation helps?

Hi all..

CAn any one please tell me the procedure to find the unique house number from the given house numbers at each side end.

Thanks alot in advance,
Pradeep