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#1 2007-12-01 13:01:14

toralf
Member
Registered: 2007-11-10
Posts: 18

Convert LAT in Ytile value

Hi,

I try to convert LAT in YTile values.
Reading the wiki I got the formulas. And with this converter I got the values that the formulas should yield to.

For Zoom equal to 12 and LAT equal to 53.051600, the Ytile value should be 1333

But when I use the formula:

ytile := Floor((1 - Log( Tan(Lat * Pi / 180) + 1 / Cos(Lat * Pi / 180)) / Pi ) / 2 * 2** zoom)

I get YTile = 1737. and this is the wrong value.

Where have I done something wrong?
Thanks.


ciao toralf

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#2 2007-12-01 13:53:13

Lambertus
Administrator
From: Apeldoorn (NL)
Registered: 2007-03-17
Posts: 3,269
Website

Re: Convert LAT in Ytile value

morwen wrote:

Please tell toralf that the answer to his question is to make sure to use natural log, not log10


Mapping tools: Garmin GPSmap 60CSx, Giant Terrago 2002

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#3 2007-12-01 13:56:25

toralf
Member
Registered: 2007-11-10
Posts: 18

Re: Convert LAT in Ytile value

Thank you.
That was the problem. I had to use LN()
Much appreciated


ciao toralf

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