update table coordinates with coordinates of a new projection

[Kostas]

Hello to all the members of the forum

I've been having the following problem.

I have to maps one with points and one with polygons each in different
projections. I want to use the select command to select some of the
points of the first map that are inside some of the polygons of the
second map. The maps are not plotted correctly when i put them
together e.g. the points are not in the place that are supposed to be.
But when i open a separate map for each all looks ok. I tried to save
both in the same projection but nothing

So i thought that the best thing to do is to update my point map
coordinates to the projection of the polygon map.

My table has 2 columns with X,Y coordinates in meters since it a LAEA.
I want to update these values written in my table column with the
coordinates of a new projection (lambert comforman conic).

I have read in various other answers in the forum that if save my map
with save as, projection button etc to another projection and then use
the update my column with the centroid(X) function i get my new
coordinates but all i get its the same coordinates as before in
degrees.

I must be doing something wrong.

Any thought on the above?

Thnaks in advance

[Thoern]

did you try "save copy as">"Save As">hit "proj buttn"> "save as"
Myreproj.tab
It should reproject if the coord system is set.
other wise you cluld open up the mapbasic window
and se what desirable code you need to reproject the coordinates to
the new coordsys.

it is the set cordsys(xxxxxxxxxxxxxxxxxxxxxxxxxxxxx) that reprojects

[David R Sherrod]

Thoern's reply is probably the route you might test first.  MapInfo keeps track of the projection of its tables and the projection of its windows, and these need not be the same.

It confuses me from time to time, so I follow a standard route when I'm trying to fill columns with coordinates of desired format (degrees or meters or whatever).  I'll write this from the view of version 8.5, but I think the scheme remains into version 10.X
1.  With the map window active, from the pulldown menu, MAP->Options->Projection, and then set the projection of the map window into the scheme you want for your column update command.  Also here you must set the coordinate units you wish to be using.  It's a toggle option within the Map Options box you've already opened.

2.  From the pulldown menu, OPTIONS->Show MapBasic Window, to get the mapbasic dialog screen open.

3. In there, type (without the quotes) "Set Coordsys Window FrontWindow()"  and hit the return key.

4.  Now you can run your column update command for centroid X (the longitude in degrees or eastings in meters or whatever was set from step 1

Hopefully, et voila.
-----------------------------------------

From:	Kostas <kostasm...@gmail.com>
To:	MapInfo-L <mapi...@googlegroups.com>
Date:	05/13/2011 04:45 AM
Subject:	[MI-L] update table coordinates with coordinates of a new projection
Sent by:	mapi...@googlegroups.com

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[Peter Horsbøll Møller]

David,

At some point we added a tool called CoordinateExtractor to MapInfo Pro. You can find this tool in the Tool Manager. 

I'm not sure if it also exists with v8.5 - if so that might make it easier for your to extract coordiantes.

Peter Horsbøll Møller
Pitney Bowes Business Insight - MapInfo

2011/5/17 David R Sherrod <dshe...@usgs.gov>

[Mats Elfström]

Hi!
Just keep in mind that any and all visible table columns, labeled x y, lat long, or humpty dumpty does not necessarily have anything to do with the coordinates used for visualizing the map.
Only if they are dynamic columns, or just updated by for instance Centroid(x) they will contain a copy of the geometry used in the map table. The original poster seems aware of this, but the fact is frequently overlooked or misunderstod.

Regards, Mats.E

2011/5/17 Peter Horsbøll Møller <mapi...@horsboll-moller.dk>

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