Sometimes it may be useful to “cookie-cut” LIDAR points by polygons. The polygons may represent rectangular grids, such as quarter quads, or can be irregularly shaped. Cookie-cut allows you to use a shape file of one or more polygons. An attribute from the Shape file can be used to name the various files. This is set in the Name field. If exporting to a raster file, only the grid cells (center of) in the polygon are given a valid value. Grid cells outside the polygons are given No-data values. The filename associated with each polygon originates from an attribute of the polygon. You must select the field to use as a base filename for each polygon.
You may also apply a buffer around each polygon. Applying a buffer is particularly useful when exporting based on rectangular polygons that do not overlap. A buffer will provide an overlap in the exported files which may prevent the loss of information when computing derived attributes for raster files (e.g., slope, aspect, hillshade, etc.) using ArcGIS™. If using the buffer, a distance in map units must be specified.When exporting rasters, the extent of each polygon will be adjusted so that the corners of the raster is divisible by the cell size. The adjusted extent is at least as big as the selected extent to ensure you have selected complete coverage. If the extent divides perfectly into the cell size, no adjustment is made to the polygon extent.
How to Cookie-cut with Polygons:
- Complete the first step required in the Export Wizard.
- Select Cookie-cut by Polygons.
- Select a set of polygons form the Polygon Layers list.
- Click the Use Selected Polygons checkbox to use only the selected polygon features.
- Select a field to represent the base filename fro each polygon in the Name List.
- To apply a buffer to each polygon, click the Apply Buffers checkbox and enter a buffer distance, in map units, greater than zero.
