I am using SQL Server 2012. I have a table where I am tracking single point instances in a geography column. Storing them as a single point is working fine but I am trying to group some of them together into a new table where they would be a multipoint. I can get it working by inserting lat and long into a multipoint column like this:
DECLARE #g geography;
SET #g = geography::STMPointFromText('MULTIPOINT(-104.952784 39.524092, -104.935269 39.542652)', 4326);
INSERT INTO test(loc) values(#g)
What I want to do is select the values from a table that are already a geography data type. I am not sure if I can do this with a basic query or if I have to build it with a loop? I cannot seem to get it working either way.
Also, after I have that is there a method that will return me the center point of a multipoint column? I have been playing with some of the methods like STStartPoint and STEndpoint but I cannot seem to find a methods that return the center point?
Any help on these questions would be great and highly appreciated.
Thanks!
What you're looking for is the STCentroid() method but, unfortunately, it doesn't work for MultiPoint objects. I raised a Connect issue for this a few years back which has been closed by Microsoft as "Won't Fix", but you're welcome to vote it up anyway: https://connect.microsoft.com/SQLServer/feedback/details/588316/make-geometry-stcentroid-method-work-on-geometries-other-than-polygons
Meanwhile, you'll have to manually sum and then average the X and Y coordinate values individually to get the average "centre" of a Multipoint.
If I'm understanding your first question correctly, you have two points, stored individually as geography instances. If that's the case, you can use the STUnion method to combine them into one geography multipoint instance.
Related
I'm trying to run an INSERT query but it asks me to convert varchar to null. Here's the code:
INSERT Runtime.dbo.History (DateTime, TagName, vValue)
VALUES ('2015-09-10 09:00:00', 'ErrorComment', 'Error1')
Error message:
Error converting data type nvarchar to (null).
The problem is at the vValue column.
column vValue(nvarchar, null)
How it looks in the database:
The values inside vValue are placed by the program I'm using. I'm just trying to manually insert into the database.
Last post was with the wrong column, I apologize.
After contacting Wonderware support i found out that INSERT is not supported on the vValue column by design. It’s a string value and updates are supposed to carry out via the StringHistory table.
What is the type of the column value in the database ?
If it's float, you should insert a number, not string.
Cast "error1" to FLOAT is non-sense.
Float is a number exemple : 1.15, 12.00, 150.15
When you try to CAST "Error1" to float, he tries to transform the text "error1" to number and he can't, it's logic.
You should insert a number in the column.
I think I can help you with your problem since I've got a decent test environment to experiment with.
Runtime.dbo.History is not a table you can interact directly with, it is a View. In our case here the view is defined as:
select * from [INSQL].[Runtime].dbo.History
...Which I believe implies the History data you are viewing is from the Historian flat file storage itself, a Wonderware Proprietary system. You might see some success if you expand the SQL Server Management Studio's
Server Objects -> Linked Servers -> INSQL
...and play with the data there but I really wouldn't recommend it.
With that said, for what reason do you need to insert tag history? There might be other workarounds for the purpose you need.
I have been having some trouble converting polygons from Geometry to Geography.
I have found the following articles and have taken the steps advised but I am still unable to convert all the instances to valid geography objects.
Union start point to ensure correct orientation
blogs.msdn.com/b/edkatibah/archive/2008/08/19/working-with-invalid-data-and-the-sql-server-2008-geography-data-type-part-1b.aspx
Reduce polygon
blogs.msdn.com/b/edkatibah/archive/2009/06/05/working-with-invalid-data-and-the-sql-server-2008-geography-data-type-part-2.aspx
Buffer and negative buffer
http://www.beginningspatial.com/fixing_invalid_geography_data
Remove points from collection after reduce
http://alastaira.wordpress.com/2012/03/02/cleaning-up-artefacts-created-by-reduce/
My process thus far is the following.
Import shape file to SQL Server Developer Edition (64-bit) using Morten Nielsen's excellent Shape2Sql tool from www.sharpgis.net/page/SQL-Server-2008-Spatial-Tools.aspx
I had to import the shape file as geometry as I was getting errors about invalid geography values.
Then I tried to create geography's as per my SQL script below.
drop table [MapData].[dbo].[World_SeasSplitGeog]
SELECT
[IDX]
,[OBJECTID]
,[NAME]
,[ID]
,[Gazetteer_]
,[Shape_Leng]
,[Shape_Le_1]
,[Shape_Area]
,[ORIG_FID]
,dbo.RemoveArtefacts(GEOGRAPHY::STGeomFromWKB(shape.STUnion(shape.STStartPoint()).STBuffer(0.00001).STBuffer(-0.00001).Reduce(0.000001).STAsBinary(),4326).MakeValid()).MakeValid() as [Shape]
INTO
[MapData].[dbo].[World_SeasSplitGeog]
FROM
[MapData].[dbo].[World_SeasSplit]
The problem however is that not all the geometries are converted to valid geographies
I'm trying to write a SQL query which determine if a given point is into a polygon. (I'm using SQL Server 2008 R2).
I was following this tutorial (just copy / paste it and change some table name) and it approximatively works BUT it is not precise at all. For example, let's considerate a given point which coordinates are :
P = 45.7664, 4.87383.
If you draw a little polygon (an approximate square) around this point with 4 vertices coordinates :
S = 45.97215 4.693909, 45.687 4.674683, 45.73302 5.460205, 46.05227 5.366821, 45.97215 4.693909
the procedure given in the link below answers the point is NOT in polygon, whereas it is...
This is the output (with my own formatting text) :
(Polygon 20 is the polygon above)
But if you enlarged the square (10 times bigger in my test), the procedure answers my point is in the square.
So, I'm seeking for another algorithm, more precise.
Here is my VERTICE table, containing all vertices coordinates of each polygon of my DB
I need to check, for ALL polygons (there are a few thousands) if a given point passed in parameter is in a polygon (and if yes, which one(s)). I can do the loop by myself, but I miss a correct Point in polygon algorithm.
Could someone help me ?
Thank you very much.
SUMMARY
The corresponding SQL fiddle : http://sqlfiddle.com/#!3/0caa4/1
Your problem is that you've defined the polygon backwards. Let's explore this with the native SQL geography types
declare #s geography, #t geography, #p geography;
select #s = geography::STPolyFromText('POLYGON((45.97215 4.693909, 45.687 4.674683, 45.73302 5.460205, 46.05227 5.366821, 45.97215 4.693909))', 4326);
select #t = geography::STPolyFromText('POLYGON((46.05227 5.366821, 45.73302 5.460205, 45.687 4.674683, 45.97215 4.693909, 46.05227 5.366821))', 4326);
select #p = geography::STPointFromText('POINT(45.7664 4.87383)', 4326);
select #p.STIntersects(#s), #p.STIntersects(#t);
select #p.STBuffer(10), #s, #t;
As you can see, #s holds pretty much the whole world. In the result set viewer, if you zoom into where your "square" should be, you'll find a hole. Contrast that with #t which is the area that you expect. Also note that I ran this in SQL 2012 which improved on a limitation that existed pre-2012 that says that a geospatial instance can't cross a hemisphere boundary. If you run the above on a 2008 instance, you'll likely get an error to that effect for #s. Comment out the line defining #s and it'll run.
There's a "right-hand" rule when defining geo(graphy/metry) polygons. Imagine that you were in a car visiting the points in the order you've specified. The area that you're defining is what you'd see if you were looking out the right side of the car.
I'm using Entity Framework 5.0 and sql server geometry type.
I'm trying to take a point and find the lines that intersect a buffer of that point and meet certain attribute requirements. Is this possible?
I know of the STIntersect method but those appear to work as a comparison between two features. I have a line dataset and a single point. so i don't know how many results i could get.
You can use the STBuffer geometry method to get an area around a point and store that in a variable (or wherever!). From there, you can use STIntersects to find out if your lines. Like so:
DECLARE #g geometry, #l geometry;
SELECT #g = geometry::STGeomFromText('POINT(0 0)', 0),
#l = geometry::STGeomFromText('LINESTRING(0 1, 4 0)', 0);
SELECT #g, #l, #g.STBuffer(1), #l.STIntersects(#g.STBuffer(1));
Also, my standard caveat of using the right data type (geography vs geometry) applies if you're doing geospatial.
How can i get the index of a point which is in my LineString?
I am using SQL Server 2008 R2.
I do have a geography type where a LineString is saved in.
I want now to get the index of two points on this LineString. So that I know which one occurs first.
Is this somehow possible?
Because right now i'm doing it for my self with a while loop... but it's really slow when i've got some more data in my database :/
EDIT: Ok, right now i'm trying to follow the solution from SQL to use CHARINDEX.
Some more background info:
I do have a geo point, I do have a linestring. I did get the intersecting points with a radius around my point from the linestring. Ok, now i want to try to get with the first intersecting point the index from this point on the LineString.
So i do have in my linestring some numbers like these patterns "1.123456 or 12.123456 or 123.123456" and my search point is also something like "1.123456 or 12.123456 or 123.123456"
The Problem is, that STIntersection gives me some different numbers back which are variable at the fractional digits. I thought about some string formatting, but i don't know how i should solve this. If there would be some nice regex features i think it would make my life easyier :)
I had a look through all of these functions but couldn't find anything for my needs.
Maybe some more experienced people could help me with that.
Thanks!
In case the datatype is varchar used. Please see below.
You can use CharIndex
DECLARE #document varchar(64)
SELECT #document = 'abcdef12345wuerzelchen'
SELECT CHARINDEX('abc', #document)
Once you have got the first occurrence point, Now you can check for another.
Declare #position int
Set #position = CHARINDEX('abc', #document)
SELECT CHARINDEX('wuerzelchen', #document, #position)
For more information you can check here