Spatial - (Built-in Functions)

 

Perform a mathematical operation on an expression or a numeric property of the items on another overlay whose hook points are inside the current item.

Expression Syntax: CalcInterior(Overlay(name, {filter}), expressionorproperty, operation)

Overlay: The overlay on which to search for contained items, either as a string or using the Overlay() expression.

filter: An optional filter to apply to items on the overlay being searched.

expressionorproperty: The expression to evaluate on the contained items (optional, with Property).

operation: The mathematical operation to perform on the results.

0 = Count - the number of results

1 = Sum - the sum of the results

2 = Average - the average of the results

Example: 

CalcInterior(Overlay("All Crime",{Crimetype$="Burglary"}), "", 0)

Note: The final parameter "0" in the example means Count how many items from the specified overlay are contained in each polygon. "1" is Sum, "3" is Average. The last two parameters will only work if you specify the third parameter (property) and if the property type is a number (integer, double).

Performs a mathematical operation on a numeric property of the items on another overlay that satisfy a spatial relation with the geometry of the current item (or with a given geometry.)

Expression Syntax: CalcItems(Overlay(name, {filter}), expressionorproperty, operation, spatialtest, geometrytype, geometry)

Overlay: The overlay on which to search for items using the given spatial relation, either as a string or using the Overlay() expression.

filter An optional filter to apply to items on the overlay being searched.

expressionorproperty: The expression to evaluate on the items (optional, with Property).

operation: The mathematical operation to perform on the results

  • OP_Count - The number of results.
  • OP_Sum - The sum of the results.
  • OP_Min - The minimum result value.
  • OP_Mean - The average of the results.
  • OP_Median - The middle number in the list of results.
  • OP_Mode - The number which appears most often in the results.
  • OP_Max - The maximum result value.
  • OP_Stddev - (Standard Deviation) a measure of the spread of the results.
  • OP_Variance - The average of the squared differences from the Mean value.
  • OP_Skewness - Reduces any positive or negative skewing of the results.

spatialtest: The spatial test to apply in the search:

  • ST_Contain - Does one geometry intersect another geometry (or the geometry of an item)?
  • ST_Cross - Does one geometry cross another geometry (or the geometry of an item)?
  • ST_Disjoint - Are one geometry and another geometry (or the geometry of an item) disjoint?
  • ST_Equal - Is one geometry equal to another geometry (or the geometry of an item)?
  • ST_Intersect - Does one geometry intersect another geometry (or the geometry of an item)?
  • ST_Overlap - Does one geometry overlap another geometry (or the geometry of an item)?
  • ST_Touch - Does one geometry touch another geometry (or the geometry of an item)?
  • ST_Within - Is one geometry within another geometry (or the geometry of an item)?

The above are constants.

However there are functions with similar names. Some of them are pluralised but in other instances they are the same as the constant name, see below:

Constant Function
ST_Contain ST_Contains
ST_Cross ST_Crosses
ST_Disjoint ST_Disjoint
ST_Equal ST_Equals
ST_Intersect ST_Intersects
ST_Overlap ST_Overlaps
ST_Touch ST_Touches
ST_Within ST_Within

geometrytype: The geometry type to use in the spatial test.

  • ST_Geometry - The geometry of the candidate item must pass the testing method with the test item.
  • ST_Envelope - Does one geometry form an envelope Polygon around the extents of an Item.
  • ST_Origin - The origin of the candidate item (always a single point) must pass the testing method with the test item.

geometry: The geometry to use in the spatial test, instead of the current item's geometry.

Example:

Taking the following SWD as an example:

The Plots overlay Max_no_of_floors column expression is:

CalcItems("Domestic Buildings”,{CalcItems("Domestic Buildings","", 
OP_Count, ST_Equal, ST_Geometry)}, OP_Max, ST_Contain,ST_Geometry)

In the above expression the inner CalcItems expression (shown in blue in curly braces) calculates the number of floors in each building.

The result from this inner calculation is then used in the main CalcItems expression of the Plots overlay to derive the maximum number of floors in each plot (Max_no_of_floors schema column).

Performs a mathematical operation on the grid values of the raster items on another overlay that satisfy a spatial relation with the current item

Expression Syntax: CalcRaster(Overlay(name, {filter}), operation, rasterband)

Overlay: The overlay on which to search for raster items, either as a string or using the Overlay() expression.

filter: An optional filter to apply to items on the overlay being searched.

operation: The mathematical operation to perform on the results:

  • OP_Count - The number of results.
  • OP_Sum - The sum of the results.
  • OP_Min - The minimum result value.
  • OP_Mean - The average of the results.
  • OP_Median - The middle number in the list of results.
  • OP_Mode - The number which appears most often in the results.
  • OP_Max - The maximum result value.
  • OP_Stddev - (Standard Deviation) a measure of the spread of the results.
  • OP_Variance - The average of the squared differences from the Mean value.
  • OP_Skewness - Reduces any positive or negative skewing of the results.

rasterband: The zero-based index of the raster band to use (optional, default value is 0).

Example:

CalcRaster("Emissions",{Type$="CO2"},OP_Mean)

Gets the extents of an item as a comma-separated string in the form X1, Y1, Z1, X2, Y2, Z2.

Expression Syntax: Extents()

Example: 

Extents()

returns strings in the form:

387229.514999527,558542.869785585,0,393270.734070659,563812.869400827,0

384144.637175971,551087.748378656,0,390057.319671121,556229.211417917,0

- Find an item on another overlay that contains the current item.

Find an item on another overlay which "contains" the current expression item.

The "." (dot) operator is used to get a property from a single item found using Spatial Queries.

Use this expression carefully: where more than one item passes the spatial test, only a single item will be found.

FindContainer will find any item: a Polygon contains the current expression item if the current expression item origin is on the Polygon boundary or in the Polygon interior; a LineString contains the current expression item if current expression item origin is on the LineString; a Point contains the current expression item if the current expression item origin is co-incident with the Point.

Expression Syntax: FindContainer(Overlay(name, {filter}))

Overlay: The overlay on which to search for a containing item (either as a string or using the Overlay() expressiond.)

filter: An optional filter to apply to items on the overlay being searched.

Returns

The value of a property on the found item, if any, using the dot operator.

Example: 

FindContainer("Polygon Overlay")._area#

returns the area of the containing item on the overlay "Polygon Overlay".

- Finds an item on another overlay whose hook point is inside the current item.

Finds an item on another overlay whose origin is "contained" by the current expression item.

The "." (dot) operator is used to get a property from a single item found using Spatial Queries.

Use this expression carefully: where more than one item passes the spatial test, only a single item will be found.

The current expression item can be any kind of item: a Polygon contains the origin if the origin is on its boundary or in its interior; a LineString contains the origin if the origin is on the line; a Point contains the origin if the origin is co-incident with the Point.

Expression Syntax: FindInterior(Overlay(name, {filter}))

Overlay: The overlay on which to search for a containing item (either as a string or using the Overlay() expressiond.)

filter: An optional filter to apply to items on the overlay being searched.

Returns

The value of a property on the found item, if any, using the dot operator.

Example: 

FindInterior("Place Names")._text$

Returns the text of the contained item on the overlay "Place Names".

Finds an item on another overlay that satisfies a spatial test with the current item.

The current expression item can be any kind of item. The found item will depend upon the chosen geometrytest and geometrymode.

Where more than one item passes the spatial test, only a single item will be found. Care should therefore be taken when using this expression.

Expression Syntax: FindItem(Overlay(name, {filter}), geometrytest, geometrymode)

Overlay: The overlay to be searched.

filter: An optional filter to apply to items on the overlay being searched.

geometrytest: The spatial test to apply

0 Equal

The two items' geometry must be the same.
1 Disjoint

The items must be completely separate, with daylight between them.
2 Intersect

The items must not be disjoint, so they must have a point in common. This is the fastest, and most common test.
3 Touch

The items' interiors must be disjoint, and their boundaries must intersect.
4 Cross

If the items are LineString items, then they must intersect without being tangential. Otherwise, their interiors must intersect, with the test item going outside the candidate item.
5 Crossed By

If the items are LineString items, then they must intersect without being tangential. Otherwise, their interiors must intersect, with the candidate item going outside the test item.
6 Within

The interior of the test item must be strictly inside the candidate item.
7 Contain

The interior of the candidate item must be strictly inside the test item.
8 Overlap

If the two items are LineString items, then they must be tangential, and neither should contain the other. Otherwise, their interiors must intersect, with neither containing the other.

geometrymode: The testing mode to apply:

0 Origin

The origin of the candidate item (always a single point) must pass the testing method with the test item
1 Extent

The extents of the candidate item (always a rectangle) must pass the testing method with the test item.
2 Geometry

The geometry of the candidate item must pass the testing method with the test item.

Example: 

FindItem("Capitals",7,0).Name$

The dot operator is used to get the properties of the found item.

Finds an item on another overlay that satisfies a spatial test with the current expression item.

The current expression item can be any kind of item. The found item will depend upon the chosen geometrytest and geometrymode.

Where more than one item passes the spatial test, only a single item will be found. Care should therefore be taken when using this expression.

Expression Syntax: FindItemEx(Overlay(name, {filter), geometrytest)

Overlay: The overlay to be searched.

filter: An optional filter to apply to items on the overlay being searched.

geometrytest: The spatial test to apply

0 Equal The two items' geometry must be the same.
1 Disjoint

The items must be completely separate, with daylight between them.
2 Intersect

The items must not be disjoint, so they must have a point in common. This is the fastest, and most common test.
3 Touch

The items' interiors must be disjoint, and their boundaries must intersect.
4 Cross

If the items are LineString items, then they must intersect without being tangential. Otherwise, their interiors must intersect, with the test item going outside the candidate item.
5 Crossed By

If the items are LineString items, then they must intersect without being tangential. Otherwise, their interiors must intersect, with the candidate item going outside the test item.
6 Within

The interior of the test item must be strictly inside the candidate item.
7 Contain

The interior of the candidate item must be strictly inside the test item.
8 Overlap

If the two items are LineString items, then they must be tangential, and neither should contain the other. Otherwise, their interiors must intersect, with neither containing the other.

Examples:

FindItemEx("Capitals", "Contain").Name$

FindItemEx("Rivers", "Intersect")._length#

The dot operator is used to get the properties of the found item.

Gets the GeoJSON representation of the geometry of an item.

Expression Syntax: GeoJSON()

Example: 

GeoJSON()

Examples of GeoJSON returns:

Polygon Item:

{"type":"Polygon","coordinates":[[[391280.189856155,583078.245016339],[400577.187441756,587453.30270368],[411104.670001921,580480.55451448],[410967.949449192,578976.628434456],[401260.790205403,577746.143459891],[391280.189856155,583078.245016339]]]}

LineString Item:

{"type":"LineString","coordinates":[[389092.661012485,572960.924114362],[413018.757740133,573371.08577255],[423682.960853028,578839.907881727]]}

Point Item:

{"type":"Point","coordinates":[406182.730103662,567355.381452455]}

- Gets the value of a Grid item on another overlay at the hook point of the current item.

Expression Syntax: Grid(Overlay(name, {filter}))

Overlay: The overlay on which to search for a Grid item.

filter: An optional filter to apply to items on the overlay being searched.

Example: 

Grid("Overlay 1")

returns the value of the found Grid item, if any, at the origin of the current expression item.

Gets the origin of an item as a comma-separated string.

Expression Syntax: Origin

Example: 

Origin()

Returns the origin of an item as a comma-separated string.

Example of a return:

535987.39641134,324946.295223841,100

Gets the area of overlay between an item on another overlay and the current expression item.

The current formula item and the overlapping items, must be closed area items, e.g. Polygon, Bitmap, QZone, TopoPolygon items, or Surface item which are TINs.

Expression Syntax: OverlapArea(Overlay(name, {filter}), expressionorproperty, valueorrange)

name: The overlay on which to search for items.

filter: An optional filter to apply to items on the overlay being searched.

expressionorproperty: The property to look for on any items found. Setting both this argument and valueorrange to empty will force all items to be considered.

valueorrange

A string value or range of numerical values. The found item will only be included in the overlap calculation if expressionorproperty is empty, or if the found item value matches valueorrange for string values or is in the range min#,max# for numerical values.

Example: 

OverlapArea("Counties","County$","Hertfordshire")

returns the overlap between the current expression item and the item representing "Hertfordshire" on the overlay "Counties".

A reference to another Overlay, used for finding items, with an optional filter.

Expression Syntax: Overlay(name, filter)

Examples:

Overlay("Buildings")

Overlay("Buildings",{Type$="Industrial"})

Expression Syntax: ST_AsBinary(geometry)

geometry: the OGC Well-known Binary (WKB) representation of a geometry.

Example:

hex(ST_AsBinary(ST_GeomFromText('LINESTRING (535977.197288014 324900.285845281,536010.741071397 324881.474128924))')))

Expression Syntax: ST_AsGeoJSON(geometry)

geometry: the OGC Well-known Text (WKT) representation of a geometry.

Example: 

ST_AsGeoJSON(geometry)

returns the GeoSON for the overlay Items. For example:

Polygon Item:

{"type":"Polygon","coordinates":[[[535984.246,324925.094],[535972.19,324917.31],[535974.3,324913.9],[535977.54,324915.94],[535976.74,324917.03],[535980.34,324919.34],[535984.84,324912.23],[535978.04,324907.99],[535980.04,324904.84],[535983.04,324900.08],[535984.44,324900.84],[535985.34,324901.44],[535983.85,324904.23],[535989.21,324907.06],[535986.8,324911.55],[535992.646,324914.707],[535984.246,324925.094]]]}

Linestring Item:

{"type":"LineString","coordinates":[[535970.608562724,324889.624669965],[535985.50001842,324897.261313912]]}

Point Item:

{"type":"Point","coordinates":[535962.238573802,324940.629044215]}

Expression Syntax: ST_AsText(geometry)

geometry: the OGC Well-known Text (WKT) representation of a geometry.

Example: 

ST_AsText(geometry)

returns the OGC Well-known Text (WKT) representation for the overlay Items, for example:

Polygon Item:

POLYGON ((535930.126230952 324933.966902089,535942.860531554 324933.966902089,535942.860531554 324918.367383851,535953.047972035 324918.367383851,535953.047972035 324911.681876035,535960.051837366 324911.681876035,535960.051837366 324894.808927738,535930.126230952 324894.808927738,535930.126230952 324923.779461607,535920.257147985 324923.779461607,535919.620432955 324931.101684453,535930.126230952 324931.101684453,535930.126230952 324933.966902089))

Linestring Item:

LINESTRING (535931.29880034 324895.979548765,536022.869128503 324895.979548765)

Point Item:

POINT (535968.131400613 324941.082338585)

Expression Syntax: ST_Centroid(geometry)

Example:

ST_AsText(ST_Centroid(geometry))

Expression Syntax: ST_Contains(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry

Example:

ST_Contains((ST_GeomFromText('POLYGON ((536000.483241777 324938.742264814,536013.217542379 324938.742264814,536013.217542379 324923.142746577,536023.404982861 324923.142746577,536023.404982861 324916.457238761,536052.693874245 324916.457238761,536052.693874245 324899.902647978,536000.483241777 324899.584290463,536000.483241777 324928.554824333,535990.614158811 324928.554824333,535989.977443781 324935.877047179,536000.483241777 324935.877047179,536000.483241777 324938.742264814))')),ST_GeomFromText('POLYGON ((536003.715008662 324908.218496757,536009.381188287 324918.870914453,536017.313839763 324919.550856008,536022.980019389 324910.938262977,536031.59261242 324908.898438312,536030.459376495 324904.592141796,536013.687484803 324904.138847426,536003.715008662 324908.218496757))'))

returns -1 if True, i.e. one of the above geometries contains the other geometry. Returns 0 if False.

Expression Syntax: ST_Crosses(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

Example:

ST_Crosses((ST_GeomFromText('LINESTRING (535940.93373841 324947.655106951,535962.238573802 324940.629044215,535970.397872463 324924.763741264,535981.276937344 324917.284384158,535989.436236005 324906.405319277,535988.75629445 324895.526254395)')),ST_GeomFromText('LINESTRING (535965.411634392 324907.311908017,535968.131400613 324920.004150378,535962.238573802 324930.656568074,535971.531108388 324936.096100515,535979.010465494 324948.561695691)'))

returns -1 if True, one of the above geometries crosses another geometry, returns 0 if False.

Expression Syntax: ST_Disjoint(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

Example:

Consider a LineString and Point Item:

ST_Disjoint((ST_GeomFromText('LINESTRING (535895.83094859 324873.994771818,535911.696251541 324883.513953589,535930.961262269 324881.247481739,535937.080736264 324868.555239377,535925.295082643 324854.729761091,535911.242957171 324851.783347685)')),ST_GeomFromText('POINT (535914.189370577 324869.008533747)'))

returns -1 if True, if one geometry and another geometry (or the geometry of an item) are disjoint, returns 0 if False.

Expression Syntax: ST_Distance(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

Examples:

Example 1:

ST_Distance((ST_GeomFromText('POLYGON ((536000.483241777 324938.742264814,536013.217542379 324938.742264814,536013.217542379 324923.142746577,536023.404982861 324923.142746577,536023.404982861 324916.457238761,536052.693874245 324916.457238761,536052.693874245 324899.902647978,536000.483241777 324899.584290463,536000.483241777 324928.554824333,535990.614158811 324928.554824333,535989.977443781 324935.877047179,536000.483241777 324935.877047179,536000.483241777 324938.742264814))')),ST_GeomFromText('POLYGON ((535824.680010114 324902.333035837,535837.414310716 324902.333035837,535837.414310716 324886.7335176,535847.601751197 324886.7335176,535847.601751197 324880.048009784,535854.605616528 324880.048009784,535854.605616528 324863.175061486,535824.680010114 324863.175061486,535824.680010114 324892.145595356,535814.810927147 324892.145595356,535814.174212117 324899.467818202,535824.680010114 324899.467818202,535824.680010114 324902.333035837))'))

Gets the distance between the first Polygon with the above coordinates and the second Polygon with the above coordinates.

Example 2:

ST_Distance((ST_GeomFromText('POLYGON ((536000.483241777 324938.742264814,536013.217542379 324938.742264814,536013.217542379 324923.142746577,536023.404982861 324923.142746577,536023.404982861 324916.457238761,536052.693874245 324916.457238761,536052.693874245 324899.902647978,536000.483241777 324899.584290463,536000.483241777 324928.554824333,535990.614158811 324928.554824333,535989.977443781 324935.877047179,536000.483241777 324935.877047179,536000.483241777 324938.742264814))')),ST_GeomFromText('LINESTRING (535977.197288014 324900.285845281,536010.741071397 324881.474128924))'))

returns the distance between the Polygon with the above coordinates and the LineString with the above coordinates.

Expression Syntax: ST_DWithin(geometry, geometry2, distance)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

distance: the distance that geometry and geometry2 must be within.

Example:

ST_Dwithin((ST_GeomFromText('POLYGON ((536000.483241777 324938.742264814,536013.217542379 324938.742264814,536013.217542379 324923.142746577,536023.404982861 324923.142746577,536023.404982861 324916.457238761,536052.693874245 324916.457238761,536052.693874245 324899.902647978,536000.483241777 324899.584290463,536000.483241777 324928.554824333,535990.614158811 324928.554824333,535989.977443781 324935.877047179,536000.483241777 324935.877047179,536000.483241777 324938.742264814))')),ST_GeomFromText('POLYGON ((536020.940194724 324883.060659219,536000.541948071 324883.060659219,536000.541948071 324861.075882272,536020.940194724 324861.075882272,536020.940194724 324883.060659219))'),200)

returns -1 if True, if one geometry and another geometry are within the specified distance, in this case 200m, returns 0 if False.

Expression Syntax: ST_Equals(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

Examples:

Example 1:

ST_Equals(Geometry, ST_GeomFromText('POLYGON ((535930.126230952 324933.966902089,535942.860531554 324933.966902089,535942.860531554 324918.367383851,535953.047972035 324918.367383851,535953.047972035 324911.681876035,535960.051837366 324911.681876035,535960.051837366 324894.808927738,535930.126230952 324894.808927738,535930.126230952 324923.779461607,535920.257147985 324923.779461607,535919.620432955 324931.101684453,535930.126230952 324931.101684453,535930.126230952 324933.966902089))'))

Gets the Polygon with the above coordinates.

Example 2:

Copy 
ST_Equals(Geometry, 
ST_GeomFromText('LINESTRING (535977.197288014 324900.285845281,536010.741071397 324881.474128924))'))

Gets the LineString with the above coordinates.

Expression Syntax: ST_GeomFromGeoJSON(geometry, crs)

geometry: the OGC Well-known Text (WKT) representation of a geometry.

crs: the coordinate reference system to be used when creating the geometry.

Example:

ST_AsGeoJSON(ST_GeomFromText('LINESTRING (535977.197288014 324900.285845281,536010.741071397 324881.474128924))',"EPSG:27700"))

Expression Syntax: ST_GeomFromText(geometry, crs)

geometry: the OGC Well-known Text (WKT) representation of a geometry.

crs: the coordinate reference system to be used when creating the geometry.

Example: 

ST_GeomFromText('LINESTRING (535977.197288014 324900.285845281,
536010.741071397 324881.474128924))',"EPSG:27700"))

Expression Syntax: ST_GeomFromWKB(geometry, crs)

geometry: the OGC Well-known Text (WKT) representation of a geometry.

crs: the coordinate reference system to be used when creating the geometry.

Example: 

ST_GeomFromWKB(ST_GeomFromText('LINESTRING (535977.197288014 324900.285845281,
536010.741071397 324881.474128924))',"EPSG:27700"))

Expression Syntax: ST_Intersects(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

Examples:

  • ST_Intersects(ST_GeomFromText('LINESTRING(1 0,0 1)'),ST_GeomFromText('LINESTRING(0 0,1 1)'))
  • ST_Intersects(Geometry.Extents,ST_GeomFromText('LINESTRING(0 0, 1 1)'))
  • Note in this second example “parts” of the current geometry have also been used. 
  • As a further example consider the Polygons below intersected by a LineString (Road):

In this example the Iif expression is also used to return a value from the following list of arguments:

Iif(ST_Intersects(Geometry, ST_GeomFromText(('LINESTRING(535973 324883, 536041 324928)'))),"Yes","No")

This will create a table column (which can be renamed) giving the values Yes or No.

Expression Syntax: ST_Overlaps(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

Example:

ST_Overlaps((ST_GeomFromText('POLYGON ((535930.126230952 324933.966902089,535942.860531554 324933.966902089,535942.860531554 324918.367383851,535953.047972035 324918.367383851,535953.047972035 324911.681876035,535960.051837366 324911.681876035,535960.051837366 324894.808927738,535930.126230952 324894.808927738,535930.126230952 324923.779461607,535920.257147985 324923.779461607,535919.620432955 324931.101684453,535930.126230952 324931.101684453,535930.126230952 324933.966902089))')),ST_GeomFromText('POLYGON ((535949.667640685 324901.241259763,535962.401941287 324901.241259763,535962.401941287 324885.641741526,535972.589381768 324885.641741526,535972.589381768 324878.95623371,535979.593247099 324878.95623371,535979.593247099 324862.083285412,535949.667640685 324862.083285412,535949.667640685 324891.053819281,535939.798557718 324891.053819281,535939.161842688 324898.376042127,535949.667640685 324898.376042127,535949.667640685 324901.241259763))'))

returns -1 if True, one of the above geometries overlaps the other geometry, returns 0 if False.

Expression Syntax: ST_PointOnSurface(geometry)

Example:

ST_AsText(ST_PointOnSurface(geometry))

Expression Syntax: ST_Relate(geometry, geometry2, de9im)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

de9im: Dimensionally Extended nine-Intersection Model. Characters can be T, F * and 0.

Example:

IIf(ST_Relate(Geometry, ST_GeomFromText('POLYGON ((536031.991371395 324915.406193349,535992.080560111 324915.406193349,535992.080560111 324898.285593934,536031.991371395 324898.285593934,536031.991371395 324915.406193349))'), "2********"),"True","False")

returns True or False

Expression Syntax: ST_Touches(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

Example:

ST_Touches((ST_GeomFromText('POLYGON ((535916.229195242 324882.607364849,535901.27048103 324882.607364849,535901.27048103 324873.541477448,535916.229195242 324873.541477448,535916.229195242 324882.607364849))')),ST_GeomFromText('POLYGON ((535916.229195242 324873.541477448,535892.884535184 324873.541477448,535892.884535184 324859.715999161,535916.229195242 324859.715999161,535916.229195242 324873.541477448))'))

returns -1 if True, one of the above geometries touches the other geometry, returns 0 if False.

Expression Syntax: ST_Within(geometry, geometry2)

geometry: the OGC Well-known Text (WKT) representation of the first geometry.

geometry2: the OGC Well-known Text (WKT) representation of the second geometry.

Example:

ST_Within((ST_GeomFromText('POLYGON ((536003.715008662 324908.218496757,536009.381188287 324918.870914453,536017.313839763 324919.550856008,536022.980019389 324910.938262977,536031.59261242 324908.898438312,536030.459376495 324904.592141796,536013.687484803 324904.138847426,536003.715008662 324908.218496757))')),ST_GeomFromText('POLYGON ((536000.483241777 324938.742264814,536013.217542379 324938.742264814,536013.217542379 324923.142746577,536023.404982861 324923.142746577,536023.404982861 324916.457238761,536052.693874245 324916.457238761,536052.693874245 324899.902647978,536000.483241777 324899.584290463,536000.483241777 324928.554824333,535990.614158811 324928.554824333,535989.977443781 324935.877047179,536000.483241777 324935.877047179,536000.483241777 324938.742264814))'))

returns -1 if True, one of the above geometries is within the other geometry, returns 0 if False.

- Gets the value of a TIN item on another overlay at the hook point of the current item.

Expression Syntax: Tin(Overlay(name, {filter}))

Overlay: The overlay on which to search for the value of a TIN item, either as a string or using the Overlay() expression.

filter: An optional filter to apply to items on the overlay being searched.

Example: 

Tin("Overlay 1")

gets the height (Z value) of the TIN in Overlay 1 at the position of the current item.

Gets the OGC Well-known Binary (WKB) representation of the geometry of an item.

Expression Syntax: WKB()

WKB() is equal to ST_ASBinary(Geometry)

“Geometry” in this case is the built-in Function.

Example: 

hex(WKB())

will return a readable result from the returned (ã) array of bytes.

Gets the OGC Well-known Text (WKT) representation of the geometry of an item.

Expression Syntax: WKT()

Example: 

WKT()

will return the OGC Well-known Text (WKT) representation for the overlay Items, for example:

Polygon:

POLYGON ((535930.126230952 324933.966902089,535942.860531554 324933.966902089,535942.860531554 324918.367383851,535953.047972035 324918.367383851,535953.047972035 324911.681876035,535960.051837366 324911.681876035,535960.051837366 324894.808927738,535930.126230952 324894.808927738,535930.126230952 324923.779461607,535920.257147985 324923.779461607,535919.620432955 324931.101684453,535930.126230952 324931.101684453,535930.126230952 324933.966902089))

Linestring:

LINESTRING (535931.29880034 324895.979548765,536022.869128503 324895.979548765)

Point:

POINT (535968.131400613 324941.082338585)