LMS Analyst MultiBuffer

MultiBuffer

MultiBuffer creates multiple, nested buffers around features.


From the LMS Analyst menu, select Multi-Buffer.

 

A dialog will open with various widgets. Select the theme to buffer by clicking in the Select Theme to Buffer listbox. Specify a list of buffer values. The list can be delimited by a comma, semicolon, or space. Only numeric values will be accepted. When the input theme and the buffer distances have been specified, the Run button will be available.

 

After you click the Run button, you will need to specify the name and location of the output shapefile. The shapefile will be given a default name based on the name of the input theme and the buffer list.

 

When you click OK, the buffering process will start. A number of status bars will show the progress as the process continues. Once the process is complete, the new theme will be added to the view.

 

Each feature has attribute values for the buffer distance, area, and perimeter. Multi-part shapes are automatically exploded into single-part shapes.

 


If you have a selection of input features, you have the option of buffering only the selected set. Here is a selected set of streams.

 

If there is a selection on the input theme, when you select the theme, the Buffer Selection? checkbox will automatically become checked. You can uncheck it if you want to run buffers on all features, not just the selected set.

 

Here is the result of running the buffer on the selected set of streams.

 


You also have the option of clipping your buffers down to a bounding polygon theme. You may want to use a property boundary or a forest stands polygon theme to limit the spatial extent of the buffers. In this example, a clipping theme is specified (forest stands). If there are a number of polygon features in the clipping theme, the features are virtually merged before the clip.

 

In the result, you can see how the buffers do not extend beyond the edge of the bounding stands.

 

And here is a similar buffer performed without the clipping. Clearly, the buffers extend beyond the bounding polygon if clipping is not enabled.

 


If there is a selection on the clipping polygon theme, you will have the option of using only the selected polygons for the clip. The Use Selection for Clip checkbox will be automatically selected. If you do not want to clip using only the selected polygons, uncheck the box.

 

Here is a selection on the clipping theme.

 

And the result of the buffer performed with a selected clipping region.

 

You can also combine selections on the input theme and the clipping polygon:

A selection is made on the streams

 

A selection is also made on the clipping theme

 

Both the input and clipping theme selection checkboxes are selected.

 

The output buffers are created only for the selected features, but clipped by the selected polygons.

 

Here is a larger scale display.


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Phil Hurvitz, GIS Specialist
phurvitz@u.washington.edu