Re: Dislocated Mercator Projection

Hi Don,

Thanks for your answer, I´m starting OpenMap with the scale=230.000
and I tried to zoom in until scale=7.187 and zoom out until scale=920.000,
but the dislocation of the map as whole keeps the same.

Talking with Mr.Alexander, he noticed the following:
___________________________________________________________________
-23.576 --> -23 0.576*60 = -23 34.56
-46.745 --> -46 0.745*60 = -46 44.7

The guess was that you were trying to compare Lat, Lon in decimal degree
with coordinates in Degree.Minute form. What I did is just converted
fractional part of degree to minutes.
Just double check this. Probably everything works fine and you don't need
any correction
____________________________________________________________________

....the problem is that, I must do something!!!! I don´t know where and how
I can adjust the projection in the right coordinates (slide up the map).

This information should helps, for each Shapefile *.shp there is a file
called *.prj with following lines:

&REM Clark 1866 Lat/Lon, Degrees, -180 ==> +180
&REM LL
PROJECTION GEOGRAPHIC
UNITS DD
PARAMETERS

Thanks for any help.

Best Regards,

Orlando

>From: Don Dietrick <dietrick@bbn.com>
>To: "orlando feitosa" <snapsurf@hotmail.com>
>CC: openmap-users@bbn.com
>Subject: Re: Dislocated Mercator Projection
>Date: Sun, 17 Mar 2002 16:06:33 -0500
>
>Hi Orlando,
>
>What scale is the map that you are looking at? Does the error decrease
>when you zoom in? You may be seeing the effects of rounding that the
>projection is doing at smaller scales, setting a pixel's coordinates to
>some value, while rounding other lat/lon values to that closest pixel as
>well.
>
>- Don
>
>On Saturday, March 16, 2002, at 10:50 PM, orlando feitosa wrote:
>
>>Hi Friends,
>>
>>Iím having a problem with the Mercator Projection, when a map (a
>>Shapefile) is rendered using the ShapeLayer, all the projection
>>appears dislocated in a wrong LAT/LON coordinates.
>>
>>Here are differences in a specific coordinate:
>>
>> Wrong Projection Should be Difference in Decimal Degrees
>>LAT -23.576 -23.346 -230
>>LON -46.745 -46.445 -300
>>
>>Is there a kind of adjustment parameter to setup this dislocation?
>>
>>Iíll appreciate any help.
>>
>>Best Regards,
>>
>>Orlando
>>
>>
>>_________________________________________________________________
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>>
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>>
>>
>
>
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>Don Dietrick, dietrick@bbn.com
>BBN Technologies, Cambridge, MA
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
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_________________________________________________________________
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