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Creates a geographic file of features on a regular grid.
In Version 5.0 the Field Width and Format options are no longer available.
max_weight = CreateGrid(real x_origin, real y_origin, integer num_rows,integer num_cols, real x_step, real y_step, string new_db_name, string layer_type, array options)
Argument |
Contents |
x_origin |
Local X coordinate of the grid's origin, in millionths of degrees |
y_origin |
Local Y coordinate of the grid's origin, in millionths of degrees |
num_rows |
Number of rows in the grid |
num_cols |
Number of columns in the grid |
x_step |
Local X coordinate increment between columns in the grid, in millionths of degrees |
y_step |
Local Y coordinate increment between rows in the grid, in millionths of degrees |
new_db_name |
The path and file name of the new geographic file |
layer_type |
The type of features to create: Point, Line, or Area |
Option |
Type |
Contents |
Density |
Array |
Array of four elements; only works for rectangular areas: - String layer|set: source points - String fieldname: field with values - String type: "Quartic" (approximating to Normal-Gaussian), "Triangular", or "Uniform") - Real radius (search radius in current user units; also call bandwidth) |
Hexagonal |
Boolean |
Create an hexagonal grid (defaults to "False") |
Label |
String |
A descriptive label for the geographic file |
Layer Name |
String |
The name of the layer in the geographic file |
Median Split |
Boolean |
If "True" special handling insures that entities which cross the 180 degree longitude line are created properly; if "False" (the default), no special handling is invoked |
NAD Conversion |
3 strings |
Input datum, output datum, and conversion file (if needed); the input and output datums should be different |
Node Layer Name |
String |
The desired name for the endpoint layer (only when creating a line layer) |
Optimize |
Boolean |
Whether to optimize the geographic file automatically after creation (defaults to "True") |
Projection |
String, array |
The projection name and the array of options |
Shape Points |
Integer |
Number of shape points per grid edge (only for line and area layers); minimum of 2 (defaults to 10) |
Table Filename |
String |
The path and file name in which attributes are stored; the file extension must be .BIN, .CSV, .DBF, or .TXT; a required option |
Temp Path |
String |
The path and file name for temporary files |
Transform |
Array |
Array indicating the transformation to apply to coordinates in the file. This can have two forms: (1) an array of two or more four-element arrays containing local and world coordinates for control points, for example, {{real localX1, real localY1, real longitude1, real latitude1}, ...}. (2) an array of four elements: {real X_multiplier, real Y_multiplier, real X_offset, real Y_offset} |
The maximum weight, only returned when the Density option is used
If the Projection option is not used then a non-projected grid is generated.
The coordinate increments must be positive.
Point grid CDFs are supported when new_db_name ends in .cdf.
CDFs are faster and more efficient than DBDs and are the preferred output geograpic file type.
For more details on the NAD Conversion option, see Datum Conversions.
For more details on the Projection option, see Using Projections and Coordinate Systems.
CreateGrid() displays a progress bar. To add a Cancel button to the progress bar, precede the function call with an "on escape" clause. For more information, see Error Handling.
The origin of the grid will be in the southwest corner.
// A 30-arcsecond longitude-latitude point grid
step = (30/3600) * 1000000 // In millionths of degrees
origin_lon = -72000000 // longitude in millionths of degrees
origin_lat = 42000000 // latitude in millionths of degrees
folder = RunMacro("G30 Tutorial Folder")
CreateGrid(origin_lon, origin_lat, 10, 10, step, step, folder + "mygrid1.CDF", "Point",{
{"Label", "30-arcsecond Grid"},
{"Layer Name", "Grid"},
{"Optimize", "True"},
{"Table Filename", folder + "mygrid1.bin"}
})
// Open mygrid1.dbd in the Tutorial folder to see the results.
// A UTM line grid
folder = RunMacro("G30 Tutorial Folder")
CreateGrid(300000, 4650000, 100, 100, 10000, 10000, folder + "mygrid2.CDF", "Line",
{
{"Label", "UTM Grid"},
{"Layer Name", "Grid"},
{"Optimize", "True"},
{"Projection", "utm", {"zone=19", "units=m"}},
{"Shape Points", 8},
{"Table Filename", folder + "mygrid2.bin"}
})
// Open mygrid2.dbd in the Tutorial folder to see the results.
// A 30-arcsecond longitude-latitude point grid
step = (30/3600) * 1000000 // In millionths of degrees
origin_lon = -72000000 // longitude in millionths of degrees
origin_lat = 42000000 // latitudein millionths of degrees
folder = RunMacro("G30 Tutorial Folder")
CreateGrid(origin_lon, origin_lat, 180, 360, step, step, folder + "mygrid3.dbd",
"Line",{
{"Label", "1 Degree Grid"},
{"Layer Name", "1 Degree Grid"},
{"Optimize", "True"},
{"Table Filename", folder + "mygrid3.bin"}
})
// Open mygrid3.dbd in the Tutorial folder to see the results..
Error Type |
Meaning |
Error |
An argument or option has the wrong type or the wrong number of values |
Escape |
The user clicked Cancel |
Function |
Summary |
Imports features from a Caliper text geography file into a geographic file |
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