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Raster

Hypsometric curves

Kuvaus

Calculate hypsometric curves for features of polygon layer and save them as CSV file for further processing.

Parameters

DEM to analyze [raster]
DEM to use for calculating altitudes.
Boundary layer [vector: polygon]
Polygonal vector layer with boundaries of areas used to calculate hypsometric curves.
Step [number]

Distance between curves.

Default: 100.0

Use % of area instead of absolute value [boolean]

Write area percentage to “Area” field of the CSV file instead of absolute area value.

Default: False

Tulokset

Output directory [directory]

Directory where output will be saved. For each feature from input vector layer CSV file with area and altitude values will be created.

File name consists of prefix hystogram_ followed by layer name and feature ID.

Console usage

processing.runalg('qgis:hypsometriccurves', input_dem, boundary_layer, step, use_percentage, output_directory)

See also

Raster layer statistics

Kuvaus

Calculates basic statistics of the raster layer.

Parameters

Input layer [raster]
Raster to analyze.

Tulokset

Statistics [html]
Analysis results in HTML format.
Minimum value [number]
Minimum cell value.
Maximum value [number]
Maximum cell value.
Sum [number]
Sum of all cells values.
Mean value [number]
Mean cell value.
valid cells count [number]
Number of cells with data.
No-data cells count [number]
Number of NODATA cells.
Standard deviation [number]
Standard deviation of cells values.

Console usage

processing.runalg('qgis:rasterlayerstatistics', input, output_html_file)

See also

Zonal Statistics

Kuvaus

Calculates some statistics values for pixels of input raster inside certain zones, defined as polygon layer.

Following values calculated for each zone:

  • minimum
  • maximum
  • sum
  • count
  • mean
  • standard deviation
  • number of unique values
  • range
  • variance

Parameters

Raster layer [raster]
Raster to analyze.
Raster band [number]

Number of raster band to analyze.

Default: 1

Vector layer containing zones [vector: polygon]
Layer with zones boundaries.
Output column prefix [string]

Prefix for output fields.

Default: _

Load whole raster in memory [boolean]

Determines if raster band will be loaded in memory (True) or readed by chunks (False). Useful only when disk IO or raster scanning inefficiencies are your limiting factor.

Default: True

Tulokset

Output layer [vector]
The resulting layer. Basically this is same layer as zones layer with new columns containing statistics added.

Console usage

processing.runalg('qgis:zonalstatistics', input_raster, raster_band, input_vector, column_prefix, global_extent, output_layer)

See also