tnxy.adf - X and Y coordinates of the points of the TIN Contains and array of X and Y coordinate values, one pair for each point of the TIN. The
data set for each point can be described by the following structure:
tnz.adf - Z coordinates of the points of the TIN Contains an array of Z coordinate values, one for each point of the TIN. The values are in same order as the values in tnxy.adf and together store the 3 dimensional coordinate of each point of the TIN. The data set for each point can be described by the following structure:
tnod.adf - Indices of the points that form the triangles of the TIN Contains an array of indices to the points that form the triangles of the TIN, 3 indices for each triangle. The indices are in the range of 1 to the number of points ([1, # of points]). The front face of a triangle (usually the upper side) is that face, that has the 3 points/corners ordered
clockwise when viewed. The data set for each triangle can be described by the following structure:
tedg.adf - Topology of the triangles and the type of its edges Contains information about the topology of the triangles and the type of their edges. There is an entry for each triangle with each 3 indices, that point to the position (number of the index) in tnod.adf file to identify the triangle, that shares an edge with the triangle described by the current data set, and the point of that triangle, that form that edge. For each triangle in tnod.adf exists a data set at the same file location in tedg.adf. Each of the values point to the location in tnod.adf, where the point is specified (the index of that point) that form an edge. At the same time, since the location in tnod.adf and tedg.adf correspond, each of the values point to the location in tedg.adf, where the location of the value is specified.
Rule: If edge
a of triangle
A points to edge
b of triangle
B, then edge
b of triangle
B must point to edge
a of triangle
A. Since edge definition in tedg.adf and point definition in tnod.adf of each triangle are at the same location the files, the indices in tedg.adf point to the point definition in tnod.adf of the neighbouring triangles. The indices encode the actual index and type of the edge. The actual indices are not file offsets in bytes, but rather in int32 values, in the range of 1 to the number of points ([1, # of points]). If the value is negative (bit 31 is set) the edge is a breaking edge. Furthermore, bit 30 of the int32 values is used to determine if the edge is a hard or soft breaking edge. If the actual index would be 1234 (0x000004D2) then a hard breaking edge would be encoded as -1234 (0xFFFFFB2E) and a soft breaking edge as -1073743058 (0xBFFFB2E). The edge definition of the neighbouring triangle must mirror the edge type. '''ATTENTION: This behaviour has changed since ArcGIS 10. Please compare with the information given in section '
Format changes and files new with ArcGIS 10'.''' The data set for each triangle can be described by the following structure:
tdenv.adf - Header or statistics This file contains information that could be seen as a mix of file header and statistic data.
thul.adf - Hull, bounding polygon and holes Contains an array of indices and separators, that defines the outer boundary of the TIN and its holes. The indices are in the range of 1 to the number of points ([1, # of points]). The separators are -1 (0xFFFFFFFF) and zero (0). If the TIN is constructed using
superpoints (usually the first 4 points), thul.adf lists the indices of these points and then -1 (0xFFFFFFFF). After the separator follows one or more lists of indices that form bounding polygons (outer boundaries) and maybe holes (inner boundaries). These lists are separated by zero (0) values. If the TIN does not contain
superpoints, thul.adf starts with the -1 (0xFFFFFFFF) separator, which is followed by one or more lists of indices that form bounding polygons (outer boundaries) and maybe holes (inner boundaries). These lists are separated by zero (0) values. The indices and separators are 4 byte integer values (int32), stored in big-endian byte order.
tmsk.adf - Mask Contains an array of bits (stored in 4 byte integers) that specify the visibility of the triangles of the TIN. This can be used to hide the triangles inside of terrain holes or outside the terrain (outside the outer boundaries). The file is stored using the same structures (header and records) as a
shapefile, but since it only stores the visibility values of the triangles many fields of the header are used. The file header is fixed at 100 bytes in length and contains 17 fields; nine 4-byte (32-bit signed integer or int32) integer fields followed by eight 8-byte (
double) signed floating point fields: The file then contains at least 2 records. Each record is prefixed with a record-header of 8 bytes: Following the record header is the actual data.
Record 1: The data of record number 1 is 2 word long and contains only the size of the data of record number 2 in 4 byte integers, stored as 4 byte integer (big-endian) itself.
Record 2: The data of record number 2 contain the following variable length structure: Bit 0 (least significant bit) of the first integer contains the visibility flag (invisible if set to 1) of the first triangle defined in tnod.adf. Bit 1 of the first integer contains the visibility flag (invisible if set to 1) of the second triangle, and so on. All 32 bits of the integers get used (no
sign bit).
Record 0: Records with the record number 0 must be ignored.
tmsx.adf - Index file for the mask The index file contains the same 100-byte header as the tmsk.adf file, followed by any number of 8-byte fixed-length records which consist of the following two fields: Using this index, it is possible to seek backwards in the tmsk.adf file by, first, seeking backwards in the index (which is possible because it uses fixed-length records), then reading the record offset, and using that offset to seek to the correct position in the tmsk.adf file. It is also possible to seek forwards an arbitrary number of records using the same method. == Optional files ==