GridAsciiDataSet Class
A datasets that reads raster files in the ARC/INFO GridASCII format.
NuGet/Assembly: Carmenta.Engine.5.16.2.nupkg (in the CEDataSets assembly)
Syntax
public class GridAsciiDataSet : MultiFileDataSetRemarks
This dataset reads files in the ARC/INFO GridASCII format. Raster values in GridASCII are floating point values, but the dataset produces integer rasters. The process when converting floats to integers can be controlled with the properties Factor and BitDepth: The raster float value is multiplied with Factor, rounded to an integer and clamped to the min and max values of the raster, calculated from the bit depth.
Due to the fact that values are stored as text (ASCII), GridASCII data is terribly slow to read. Try using binary data and a binary reader like HdrDataSet instead.
The GridASCII files might look like this:
ncols 1000
nrows 1000
xllcorner 1325000.0
yllcorner 6275000.0
cellsize 25.0
nodata_value -9999.0
71.0 71.0 71.0 71.0 71.0 71.0 71.0 71.0 61.0 61.0 62.0 62.0 71.0 71.0 71.0 93.0 ...
Description:
Line | Tag | Type | Description |
|---|---|---|---|
1 | ncols | Integer | Number of columns in raster. |
2 | nrows | Integer | Number of rows in raster. |
3 | xllcorner OR xllcenter | Float | If this line is tagged xllcorner then it is the coordinate for the corner of the lower left pixel in the raster. If this line is tagged xllcenter then it is the coordinate for the center of the lower left pixel in the raster. |
4 | yllcorner OR yllcenter | Float | If this line is tagged yllcorner then it is the coordinate for the corner of the lower left pixel in the raster. If this line is tagged yllcenter then it is the coordinate for the center of the lower left pixel in the raster. |
5 | cellsize | Float | The resolution of one pixel. |
6 | nodata_value | Float | Optional. Value that should be treated as the undefined value of the raster. If there are no undefined values in the raster this line is excluded. |
7...n | Floats | The actual raster values. If the nodata_value line is excluded, the raster values start at line 6. |
Inheritance Hierarchy
System.Object (not available in C#)
EngineObject
ResourceObject
DataSet
FileDataSet
MultiFileDataSet
GridAsciiDataSet
Platforms
Windows, Linux, Android
GridAsciiDataSet Members
The GridAsciiDataSet type has the following members.
Constructors
| Name | Description |
|---|---|
| GridAsciiDataSet | Initializes a new instance of the GridAsciiDataSet class. |
Properties
| Name | Description |
|---|---|
| BitDepth | Gets or sets the bit depth of the created rasters. |
| Continuous | Gets or sets a flag indicating if rasters created by this dataset should be interpreted as continuous or discrete. |
| Crs | Gets or sets the coordinate reference system of the GridAsciiDataSet. Inherited from DataSet |
| Description | Gets or sets a short description of the dataset. Inherited from DataSet |
| DisplayName | Gets or sets a display name for the dataset. Inherited from DataSet |
| Factor | Gets or sets a factor multiplied the raster values. |
| FileName | Gets or sets the name of the file to read from. Inherited from FileDataSet |
| Id | Gets a unique identifier for this dataset instance. Inherited from DataSet |
| IndexFileName | Gets or sets an explicit index file name used for the generated index files in IndexPath. Inherited from MultiFileDataSet |
| IndexPath | Gets or sets the directory where the dataset index files are saved. Inherited from MultiFileDataSet |
| IsDisposed | Gets a value that tells whether the current GridAsciiDataSet has been disposed. Inherited from EngineObject |
| IsoMetadataDocument | Gets or sets the path to an ISO 19139 metadata document for the dataset. Inherited from DataSet |
| Name | Gets or sets the name of the GridAsciiDataSet. Inherited from ResourceObject |
| NativeHandle | Gets the native Carmenta Engine kernel object the current GridAsciiDataSet represents. Inherited from EngineObject |
| Path | Gets or sets the path to the file or files to read from. Inherited from FileDataSet |
| RasterCacheCompression | Gets or sets a value that controls which method is used to compress the tiles in a raster cache. |
| RasterCacheFilter | Gets or sets the down-sampling filter to use when creating raster overviews. |
| RasterCachePolicy | Gets or sets a value indicating the type of raster caching the dataset should use. |
| SearchSubdirectories | Gets or sets a flag indicating if the dataset will search for data files recursively. Inherited from MultiFileDataSet |
| SuppressInitializationErrors | Gets or sets a flag indicating how errors during dataset initialization are handled. Inherited from DataSet |
| IUserProperties.UserProperties | Gets the AttributeSet that contains the user properties. Inherited from IUserProperties |
| VerifyIndexFiles | Gets or sets a flag indicating if the contents of index files should be verified before use. Inherited from MultiFileDataSet |
Methods
| Name | Description |
|---|---|
| Clone | Creates a copy of an object. Inherited from EngineObject |
| Dispose | Releases the reference to the native Carmenta Engine kernel instance the EngineObject represents. Inherited from EngineObject |
| Equals | Determines whether this instance is equal to another. Inherited from EngineObject |
| FindChildObject | Overloaded. Finds the child object with the specified name. Inherited from DataSet |
| FlushCache | Frees any information the dataset may have cached, including all cached features. Inherited from DataSet |
| GetChildObjects | Overloaded. Gets the child objects of the current object. Inherited from DataSet |
| GetDataCoverage | Gets coverage information for this dataset in a given area. Inherited from DataSet |
 GetDataSetById | Looks up an existing dataset instance from a dataset identity. Inherited from DataSet |
| GetDataSetInfo | Returns a dataset info that describes the contents of this dataset. Inherited from DataSet |
| GetDataSetInfoAsync | Makes an asynchronous call to GetDataSetInfo. Inherited from DataSet |
| GetFeature | Gets the feature with the specified identity. Inherited from DataSet |
| GetFeatures | Overloaded. Gets features from the dataset. Inherited from DataSet |
| GetFloatValueAt | Overloaded. Gets the float raster value from a cell at the specified position. Inherited from DataSet |
| GetFloatValuesAt | Overloaded. Gets a number of float raster values. Inherited from DataSet |
| GetLocalizedDescription | Gets a localized version of the dataset description in a specific language. Inherited from DataSet |
| GetLocalizedDisplayName | Gets a localized version of the dataset display name in a specific language. Inherited from DataSet |
| GetLocalizedIsoMetadataDocument | Gets the path to an ISO 19139 metadata document for a specific language. Inherited from DataSet |
| GetNormalizedFloatValueAt | Overloaded. Gets the raster value from a cell at the specified position, normalized by Scale and Offset. Inherited from DataSet |
| GetNormalizedFloatValuesAt | Overloaded. Gets a number of raster values, normalized by Scale and Offset. Inherited from DataSet |
| GetValueAt | Overloaded. Gets the integer value from a raster cell at the specified position. Inherited from DataSet |
| GetValuesAt | Overloaded. Gets a number of raster values. Inherited from DataSet |
| HasLocalizedDescription | Checks if a localized version of the dataset description is available in a specific language. Inherited from DataSet |
| HasLocalizedDisplayName | Checks if a localized version of the dataset display name is available in a specific language. Inherited from DataSet |
| HasLocalizedIsoMetadataDocument | Checks if an ISO 19139 metadata document is available for a specific language. Inherited from DataSet |
| HighestRasterValue | Finds the highest raster value inside the given polygon. Inherited from DataSet |
| Initialize | Initializes the dataset. Inherited from DataSet |
| SetLocalizedDescription | Sets a dataset description in a specific language. Inherited from DataSet |
| SetLocalizedDisplayName | Sets a dataset display name in a specific language. Inherited from DataSet |
| SetLocalizedIsoMetadataDocument | Sets the path to an ISO 19139 metadata document for the dataset, for a specific language. Inherited from DataSet |
| TryGetFloatValueAt | Overloaded. Gets the float value from a raster cell at the specified position. Inherited from DataSet |
| TryGetNormalizedFloatValueAt | Overloaded. Gets the float value from a raster cell at the specified position, normalized by Scale and Offset. Inherited from DataSet |
| TryGetValueAt | Overloaded. Gets the integer value from a raster cell at the specified position. Inherited from DataSet |