Peter Horsbøll MøllerSenior Systems Engineer

Pitney Bowes Software

The Power of Spatial SQL in MapInfo Professional

Peter Horsbøll MøllerSenior Systems EngineerJune 15, 2012

Every connection is a new opportunity™

Workshop agenda

• In this workshop we will play around with the spatial SQL capabilties of MapInfo Professional

• We will look at joining tables based on the spatial objects• We will calculate size of parts of the spatial objects• We will extract and insert parts into new tables

3

SQL Select

• Columns, expressions

• Tables• Conditions

4

Joining via the spatial object

• Select the two tables– Object will come from

first table

• Specify spatial condition:– Contains– Within– Intersects– Partly Within– Contains Part– Entirely Within– Contains Entire

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Contains / Within

• Comparing the Centroid!

• Order does matter• Good with points

• A Contains C• A Contains D• B Contain A• C Contains D

• C Within A• D Within A• B Within A• D Within C

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Intersects / Partly Within / Contains Part

• Comparing the entire object!

• Order doesn’t matter

• A Contains Part B• A Contains Part C• A Contains Part D• B Contain Part A• B Contains Part C• B Contains Part D• C Contains Part A• C Contains Part B• C Contains Part S• D Contains Part A• D Contains Part C

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Contains Entire / Entirely Within

• Comparing the entire object!

• Order does matter

• A Contains Entire D• C Contains Entire D

• D Entirely Within A• D Entirely Within C

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Spatial operators

• Within/Contains– Very fast– Inprecise when working with other objects than points

• Intersects/Partly Within/Contains Part– Slower then Within/Contains– Should be used when comparing lines/polylines and regions

• Entirely Within/Contains Entire– Slower then Within/Contains– To be used if one object should be ”entirely within” the other

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Specifying columns

• Pick the columns from the ”Columns” list

• Create expressions using the ”Functions” list or type in some functions manually

• Use aliases (”some new name”) for expressions

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Exercise

• Join the two tables Cadastre and Urban_Area• Join them using the Intersects operator• Select these columns

– CADASTRE.AREA_NAME– CADASTRE.LOT_NO– URBAN_AREAS.NAME

• Add these functions and aliases:– CartesianArea(CADASTRE.OBJ, "sq m") "Area_Cadastre”– CartesianArea(URBAN_AREAS.OBJ, "sq m") "Area_UrbanArea"

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Adding a overlap tolerance

• Overlap(obj1, obj2):– Creates an object where

the two objects have a common ”area”

• MapInfo Pro will create this object and calculate the area of it

• If this area is larger then 10 sq m, the intersection will be used

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Calculating area overlap

There are a number of ways to calculate the size of the overlapping area:

• CartesianArea(Overlap(obj, obj), units)– Uses the defined units– Should be used for projected data (non Longitude/Latitude data)

• SpericalArea(Overlap(obj, obj), units)– Uses the defined units– Should be used for Longitude/Latitude data

• AreaOverlap(obj, obj)– Uses the current units in MapInfo Professional– Uses the SpericalArea calculation

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Exercise

• Add a overlap tolerance by adding this to the condition:– CartesianArea(Overlap(Cadastre.obj, Urban_Areas.obj), "sq m") >

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• Try different tolerances• How do you change the unit used?

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Extracting spatial data

• By default MapInfo Professional takes the spatial object from the first table in your query

• You can however add ”more” spatial objects to your query thru the ”Column” field

• To see these extra columns you need to insert the result into a new/another table

15

Adding an extra spatial column

• Add your extra spatial object, can be an expression

• Consider using an alias

• Note that the result still will highlight the entire area from the first table

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Creating a new table

• You can consider using the structure from your first table and just modify it to match the columns in your query

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Inserting the query

• You need to do this thru the MapBasic window• Show the MapBasic Window from the Options menu• Write this:

Insert Into OverlapResult (AREA_NAME, LOT_NO, NAME, OBJ) Select AREA_NAME, LOT_NO, NAME, OverlapObj From Query1

• Where– OverlapResult is your new table– OverlapObj is your spatial column alias– Query1 is the name of yoru query

• And hit enter• Make sure your new table hasn’t been added to the map

as that will slow it down – a lot!18

Final result

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Exercise

• Add a spatial column to your result• Create a new table• Insert the result into this new table using this:Insert Into OverlapResult (AREA_NAME, LOT_NO, NAME, OBJ) Select AREA_NAME, LOT_NO, NAME, OverlapObj From Query3

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Regions and lines/polylines

• Works just like regions and regions

• Note that Overlap uses the style from the first object

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Exercise

• Find the roads that intersects the urban areas• Use these columns from the roads:

– ROADNAME– ROUTE_NO– ID

• And this column from the urban areas– NAME

• Extract only the part of the road within the urban area• Create a new table• Insert the result into this new table

Insert Into UrbanRoads (ROADNAME,ROUTE_NO,ID,NAME, OBJ) Select ROADNAME,ROUTE_NO,ID,NAME, LineOverlap From Query1

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Adding multiple spatial columns

• The SQL statement can include several spatial columns

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Select Cadastre.LOT_NO , Cadastre.AREA_NAME , Cadastre.obj "CObj" , Urban_Areas.obj "UObj" , Overlap(Cadastre.obj , Urban_Areas.obj) "JOBJ" From Cadastre, Urban_Areas Where Cadastre.Obj Intersects Urban_Areas.Obj into Selection

Extracting multiple spatial objects

• You need MapBasic to get to these ”many” spatial columns

• They could be inserted into the cosmetic layer in this way:

Fetch First From SelectionDim oTemp As ObjectoTemp = selection.UObjInsert Into WindowInfo(FrontWindow(), 10) (OBJ) Values (oTemp)

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Exercise

• Select multiple spatial columns• Insert a few of the selected spatial data into the cosmetic

layer of a map window

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Some other spatial function

• Overlap()• Erase()• Combine()

• IntersectNodes()• ExtractNodes()

• MBR()• Centroid()

• CreatePoint()• CreateLine()• Buffer() (Cart/Sper)• Offset() (Cart/Sper)• OffsetXY() (Cart/Sper)• Rotate()• RotateAtPoint()

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Thank You

Peter Horsbøll Møller

peter.moller@pb.com