Spatial data pre-processor

Owned by Former user (Deleted)
Last updated: 04 Sept 2014 by asatheesh (Unlicensed)
3 min read

As its name suggests, the spatial data pre-processor allows the manipulation of spatial data through a range of tools outlined below.

CookieCut

The CookieCut tool allows a portion of a larger raster to be "cut out" and a new raster produced. This may be useful when you only need a small segment of a large land use or DEM file.

  • Drag and drop the raster that a segment is to be "cut" from into the "dough" pane;
  • In the cutter pane drag and drop the raster that will mark the dimensions or border of the new raster; and
  • Click Run and the new segment raster is displayed in the cookie pane and can be saved using the Save icon to the left of the Cookie pane.

CreateMask

The CreateMask tool creates a new raster of the same dimensions as the source raster with grid cell values that equal the mask value. Therefore, all non-null values in the raster grid are replaced with the maskValue parameter. This can be done as follows:

  • Drag and drop a raster into the src pane. This is the source raster from which remapping will be done;
  • Enter a value for maskValue, which will replace all the non-null values in the raster grid. For example, a maskValue of 1 (default) will produce a new raster with the value of 1 in all cells that are not null values; and
  • Click Run and the new mask raster appears in the dest pane. This can be saved to disk.

ExtractRaster

The ExtractRaster tool allows a spatial layer to be extracted from a raster. Therefore, if grid code 3 is entered in the val box, then all grid codes referenced as 3 will be extracted from the source raster (src).

  • Drag and drop a raster to the src box;
  • Enter the grid code value of the layer that is to be extracted; and
  • Click Run. The extracted raster is displayed in the Output tab.

QuickRemap

The QuickRemap tool allows the grid codes of a raster file to be changed in an easy manner by changing the values in the table and running the tool to get a new raster:

  • Drag and drop a raster into the src box. This is the source raster from which remapping will be done;
  • Enter the modified grid codes that map to certain layers within the raster. For example, a forest layer in a land use map may have a grid code of 3. If a scenario is required where the forest is cleared for horticulture, the grid code may need to be changed to 5, to signify that it is a Horticulture FU; and
  • Click Run and the remapped raster appears in the dest box. This can be saved to disk.

SelectColumns FromVectors

The SelectColumnsFromVectors tool extracts a particular attribute column from a vector map (ie. shape file) and creates a new vector map based on the selected attribute.

  1. Drag and drop a vector file (such as a shape file) into the sourceData pane. A list of attributes is displayed. To display the spatial extent of the attribute, select the attribute name in the sourceData pane. The number of the attribute column is displayed under Hide.
  2. Set the attribute column number in the entryToTake pane. In the example shown a value of 1 corresponds to the GRIDCODE attribute column.
  3. Click Run. The resulting vector map is displayed in the destinationData window, which contains only the attribute in the column corresponding to the value specified in entryToTake.

StreamOrder Lengths

The StreamOrderLengths tool gives a summary of the lengths (in meters) of the river reaches and streams for each sub-catchment so that management tasks, such as riparian buffer zones, can be applied to specific stream orders within sub-catchments.

Select Tools » Plugins » RiverSystems.Plugins.SpatialDataPreProcessor » StreamOrderLengths. The Stream Order Lengths window appears:

  • Drag and drop a stream order raster into the StreamOrderRaster pane;
  • Drag and drop the sub-catchment map into the Sub Catchment Raster pane;
  • Adjust the sinuosity factor if necessary (default value is 1.25);
  • Click Create to create a table summarising the stream orders and lengths per sub-catchment; and
  • Click Save to save the table. Source saves this as a tab-delimited file (.txt).

Sub-catchment Union

The Sub-catchmentUnion tool joins all sub-catchments in a sub-catchment raster into a single catchment area:

  1. Drag and drop a sub-catchment raster into the src pane.
  2. Click BI. The resulting catchment raster is displayed in the dest pane and can be saved by clicking Save.