Hi all.Here's a partial macro for LWM Polygons( Land/Water Mask ), using Microsoft's terminology, and the BGLC code for a small pond in the Sahara ( N23*13.17' E25*17.432' ).First the Macro:

; LWMMacros.inc	 //  include file for use with BGLCLWMFileHeader		Macro	Version, IndexHeader, Data, End	LOCAL	startstart	LABEL	word	UINT32 	20				;		   // Size of this header (20 bytes)	UINT32 	Version				;			// Version (must be 0x0201)	SINT32 	( OFFSET IndexHeader ) - ( OFFSET start );	// Relative offset to index	SINT32 	( OFFSET Data ) - ( OFFSET start )	;			// Relative offset to data	SINT32 	( OFFSET End ) - ( OFFSET start )	;			 // Size of all data plus headersENDMLWMDataAreaDrawPolygons	Macro	PolyCount, Attrib, Flag, Col, Row;	UINT16 wPolyCount:3	;  // The number of polygons up to 6. For 7 or more, use LWMDataAreaDrawPolygonsEx;	UINT16 wAttrib:2	;	 // Must be 3;	UINT16 wFlag:1		;	   // Must be 1!;	UINT16 wCol:5		;		// Column, 0 to 31;	UINT16 wRow:5		;		// Row, 0 to 31	UINT16	( Row * 800h ) + ( Col * 40h ) + ( Flag * 20h ) + ( Attrib * 8h ) + PolyCountEndMLWMDataAreaDrawPolygonsEx	Macro	PolyExFlag, Attrib, Flag, Col, Row, ExPolyCount;	UINT16 wPolyExFlag:3	; // Must be 7.;	UINT16 wAttrib:2	;	 // Must be 3 (transparent);	UINT16 wFlag:1		;	   // Must be 1!;	UINT16 wCol:5		;		// Column, 0 to 31.;	UINT16 wRow:5		;		// Row, 0 to 31.	UINT16	( Row * 800h ) + ( Col * 40h ) + ( Flag * 20h ) + ( Attrib * 8h ) + PolyExFlag		BYTE  ExPolyCount	;  // The number of polygons = 7 + ExPolyCountEndMLWMDataAreaHeight	Macro	Height, Fraction	  SINT16 Height	;	// integer height in meters   	-9999 is no height data!	  BYTE  Fraction; 	// number of 1/128 meter fractions to add to Height	Zero if no height data!EndMLWMPoly2			Macro	PointCount, Reserved, Attrib, Height, Fraction;	BYTE  bPointCount:6	;   // Up to 62 points;	BYTE  bReserved:1	;	 // Must be 0;	BYTE  bAttrib:1	;	   // Polygon fill attribute, 0 = water, 1 = land	BYTE	( Attrib * 80h ) + ( Attrib * 40h ) + PointCount	SINT16 	Height		;		 // Whole elevation value in meters	BYTE	Fraction		;	   // Fractional elevation value in 1/128 metersEndMLWMPoly2Ex		Macro	PointCount, Reserved, Attrib, Height, Fraction, ExPointCount;	BYTE  bPointCount:6	;   // Must be 63;   BYTE  bReserved:1	;	 // Must be 0;	BYTE  bAttrib:1	;	   // Polygon fill attribute, 0 = water, 1 = land	BYTE	( Attrib * 80h ) + ( Attrib * 40h ) + PointCount	SINT16	Height		;	   	BYTE	Fraction		;	  	BYTE	ExPointCount	;   // Number of polygon points = 63 + bExPointCountEndMLWMIndexHeader		Macro	NumberIndexEntries, Index	LOCAL	startstart	Label 	word	UINT32 	12			;			 // Size of this header (12 bytes)	UINT32 	NumberIndexEntries	;	 // Number of entries in the index	SINT32 	( OFFSET Index ) - ( OFFSET start );			 // Relative offset to the index dataENDMLWMIndexEntry		Macro	LWMCellID, start, Data, End	LWMCellID 				;	 // Location and default attributes or the cell	SINT32	( OFFSET Data ) - ( OFFSET start );	// Offset from the beginning of the data block	SINT32	( OFFSET End ) - ( OFFSET Data );	  // Size of data blockEndMLWMCellID		Macro	RunCount, IndexRun, Attrib, U, V;	UINT32 dwRunCount:9	; 	// Number of identical indices;	UINT32 dwIndexRun:1	; 	// If this 0 = single index, 1 = a series of indices;	UINT32 dwAttrib:2	;   	// The fill attribute 0 = water, 1 = land, ;					   		; 	//	2 = flatten only, 3 = transparent;	UINT32 dwU:10		;	   	// The column (from 0 to 767) in the 768x512 world grid;	UINT32 dwV:10		;	   	// The row (from 0 to 511)	UINT32	( V * 400000h ) + ( U * 1000h ) + ( Attrib * 400h ) + ( IndexRun * 200h ) + RunCountEndMLWMPoint		Macro	x, y  BYTE	x	;  BYTE	y	;EndM

And now the BGLC code using the Macro:

include LWMmacros.inc; LWM Poly Test; ===================================================================; DATA_BASEdata_base	label	word	dw	1			; world set number	dd	2667133 	; North Bound	dd	2444872 	; South Bound	dd	310192082 	; East Bound	dd	262470223 	; West Bound	dd	0			; VOR data	dw	0			; lowest VOR freq	dw	0			; highest VOR freq	dd	0			; seeds level 8 data	dd	0			; seeds level 9 data	dd	0			; seeds level 10 data	dd	0			; seeds level 11 data	dd	0			; seeds level 12 data	dd	0			; traffic data	dd	0			; minimum safe altitude data	dd	terrain_data - data_base; terrain mesh data	dd	0			; object data	dd	0			; library data	dd	0			; facilities data	dd	0			; anchor point data	dd	0			; ATIS data	dd	0			; NDB data	dd	0			; dynamic object paths data	dd	0h,0h			; minimum library id	dd	0h,0h			; maximum library id	dd	0			; miscellaneous data	dd	0			; title and description data	dd	0			; magnetic variation data	dd	0			; exception and exclusion data	dd	87654321h		; magic number	dd	0			; compression switch	dw	0			; spare	dd	0h,0h,0h,0h		; GUID	dd	0			; product id	dd	0			; product build number	dd	0			; new facility data pointers	dd	0			; new facility name list data	dd	0			; new facility band list data	dd	0			; new facility data; ===================================================================; TERRAIN_DATAterrain_data	label	word	dd	terrain_header_end - terrain_data; end of terrain header	dd	514				; version	dd	0				; unknown entry	dd	0				; unknown entry	dd	0				; elevation header	dd	0				; land class header	dd	0				; unknown header	dd	0				; class lookup header	dd	0				; season header	dd	0				; class lookup list	dd	0				; water class header	dd	0				; elevation index	dd	0				; land cover index	dd	0				; unknown index	dd	Flatten_Header - terrain_data	; flatten polygon header	dd	0				; decal header	dd	0				; reserved	dd	0				; reserved	dd	0				; main terrain data	dd	0				; reserved	dd	0				; reserved	dd	0				; reserved	dd	0				; regions header	dd	0				; reserved	dd	0				; reservedterrain_header_end	label	word; ===================================================================; Terrain Flatten HeaderFlatten_Header	label	word	LWMFileHeader	513, Flatten_List, Flatten_Start, Flatten_End; TERRAIN FLATTEN POLYGON DATAFlatten_Start	label	word; - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - data_start_0	label	word	LWMDataAreaDrawPolygons	1, 3, 1, 30, 28	LWMPoly2		10, 0, 0, 622, 0		LWMPoint 131, 16		LWMPoint 173, 29		LWMPoint 189, 62		LWMPoint 193, 96		LWMPoint 178, 133		LWMPoint 134, 152		LWMPoint 84, 151		LWMPoint 53, 95		LWMPoint 79, 49		LWMPoint 114, 43data_end_0	label	word; - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; ===================================================================; TERRAIN FLATTEN POLYGON LISTCell_437_189	EQU	LWMCellID 1, 0, 3, 437, 189	Flatten_List	label	word		LWMIndexHeader	 1, Flatten_Groups	Flatten_Groups	label	word		LWMIndexEntry		 Cell_437_189, Flatten_Start, data_start_0, data_end_0; ===================================================================; FLATTEN_ENDFlatten_End	label	word; ===================================================================

Hi all.Completed the translation of terms for LWM polygons. Area filling is an interesting twist we hadn't guessed.A couple of attachments:3d6fbe334a5ca318.txt is the completed LWMmacros.inc3d6fbe404a8e72ab.txt is the LWMtestfill.asmDick

Thanks Dick, I can't wait til your next tutorial. :) Using the new SDK's will help ya allot I'm sure.Ken

Actually I suspected those area filling polygons. I saw polygons that had zero points, so I always suspected that would fill a LOD13 quad (otherwise what's the use). However, I haven't guessed that they can come in different sizes...Cheers, Christian