Hi all,
Sorry please ignore my last note. Thanks Peter your suggestion works like a charm!
Christine
-----Original Message-----
From: [EMAIL PROTECTED] on behalf of Ronning, Christine
Sent: Tue 6/27/2006 9:26 AM
To: Peter Horsbøll Møller; MapInfo-L@lists.directionsmag.com
Subject: [MI-L] Number of points in a buffer
Hi all,
I asked this question last week and Peter suggested the below. I'm just not sure where to include the Where OBJ in Buffer Table "Contains" OBJ in Points Table statement in the Table>Update Column window. Can anyone help? Thanks
Christine
-----Original Message-----
From: Peter Horsbøll Møller [mailto:[EMAIL PROTECTED]]
Sent: Wed 6/21/2006 2:17 PM
To: Ronning, Christine; MapInfo-L@lists.directionsmag.com
Subject: RE: [MI-L] Wrong Subject on last one: Spatial Query
Christine,
I'm sure there are a number of ways to do this. Here is mine
1. Make sure that your table contains a column with a unique ID. You could use ROWID to update a numerical column.
2. Use Table > Buffer to create a new table of buffers around your points
3. Add a column to hold the number of points, let us call it NUMPOINTS
4. Using Table > Update Column you can now update you table of buffers with the number of points that fall within each buffer.
Update Table "Buffer"
Column "NUMPOINTS"
Get Values From Table "Points"
Where OBJ in Buffer Table "Contains" OBJ in Points Table
Calculate Value "Count(*)"
4. Now do a SQL Select:
Select "*"
From "Points"
Where "ID In (Select ID from Buffers Where NUMPOINTS > 10"
I'm not sure if you want to select the points where there are 10 or more points within .5 km including the point or excl the point. But that should just be a question of comparing NUMPOINTS to 10 or 11.
HTH,
Peter Horsbøll Møller
GIS Developer, MTM
Geographical Information & IT
COWI A/S
Odensevej 95
DK-5260 Odense S.
Denmark
Tel +45 6311 4900
Direct +45 6311 4908
Mob +45 5156 1045
Fax +45 6311 4949
E-mail [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
http://www.cowi.dk/gis
________________________________
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Ronning, Christine
Sent: Wednesday, June 21, 2006 10:53 PM
To: MapInfo-L@lists.directionsmag.com
Subject: [MI-L] Wrong Subject on last one: Spatial Query
Hi all,
I have mapped a points layer.
I would like to select those records where there is more than 10 points within a radius of .5km.
I'm having trouble even starting on this one! Can anyone provide some guidance/thoughts?
Thanks
Christine
-----Original Message-----
From: [EMAIL PROTECTED] on behalf of Spencer Simpson
Sent: Wed 6/21/2006 11:34 AM
To: 'Alan Silvester'; mapinfo-l@lists.directionsmag.com
Subject: RE: [MI-L] Creating a line from a series of points
I think we need to know a little more about the table, such as:
1. Are there columns specifying X and Y, or formulas, or a point object
you can derive X and Y Coordinates from?
2. Is there a column specifying the order that a point appears in the
polyline?
3. Is there more than one polyline? If so, is there a column specifying
which polyline a row belongs to?
If so, then it's possible to write a MapBasic application to chain the
points together. Some of the other listers may have even written such
applications.
A. Sort by (select statement with order by clause) polyline specifier
and order specifier
B. Iterate through the result table. For each record:
if the line specifier changed, finish the current polyline (insert) and
start a new one with the coordinates from current rec (Create Pline).
If not, add the coordinates from the current rec to the end of the current
line. (Alter Object Add Node)
C. At the end, finish the current polyline.
Hope this helps
Spencer
_____
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]] On Behalf Of Alan
Silvester
Sent: Wednesday, June 21, 2006 11:30 AM
To: mapinfo-l@lists.directionsmag.com
Subject: [MI-L] Creating a line from a series of points
Dear All,
Does anybody know how to automatically create a line from a series of
points, i.e. rather than drawing a line from point to point, I want to be
able to make a line that automatically joins up the points. The problem is,
is that the next point to join up with the line may not be the next record
in the table?! The points are however all 1km apart.
Does anyone have any ideas?
Regards,
Alan
Alan Silvester
GIS Manager
GroundSure Limited
Unit E, Level 7
New England House
Brighton
BN1 4GH
Tel: +44 (0)1273 819500 (Switchboard)
+44 (0)1273 647811 (Direct dial)
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