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Exercise – 6 / How to use Buffer tool in QGIS తెలుగులో నేర్చుకుందాం

Exercise – 6 / How to use Buffer toolin QGIS

Buffer

Buffers are proximity functions,using this geoprocessing tool, it creates a polygon at a set distance surrounding the features.


Buffer – Line

  • Add Line layer to Layers panel

Figure 89 - Sample Line data before Buffer

  • Choose Vector → Geoprocessing tools → Buffer to open buffer window
  • Select Input Layer(Ex: Network)
  • Provide Distance for creation of Buffer around the line data.
  • Provide Segments value(The segments parameter controls the number of line segments to use to approximate a quarter circle when creating rounded offsets)
  • Select End cap style from Round, Flat, Square (The end cap style parameter controls how line endings are handled in the buffer)
  • Provide Join Style from Round, Miter, Bevel (The join style parameter specifies whether round, miter or beveled joins should be used when offsetting corners in a line)
  • Provide Miter Limit(The miter limit parameter is only applicable for miter join styles, and controls the maximum distance from the offset curve to use when creating a mitered join.)
  • Check Dissolve results
  • Click on Run


Figure 90 - Buffer window

  • Temporary layer will be created and added to Layer panel with Buffered layer. Right click on the layer and save to destination folder.

Figure 91 - Buffer Layer






  • To create Buffer with attribute value, click on to view the option.
  • Select Field type: int, double, string → Select the attribute field which contains values on which buffer to be generated.

 

Figure 92 Buffer with Attribute Value

  • Temporary layer will be created and added to Layer panel with Buffered layer. Right click on the layer and save to destination folder.

Figure 93 – Buffer Layer with Attribute value


      1. Buffer – Point

    • Add Point Layer to Layers panel

    Figure 94 - Sample Point data before Buffer

    • Choose Vector → Geoprocessing tools → Bufferto open buffer window
    • Select Input Layer(Ex: Location)
    • Provide Distance for creation of Buffer around the point data.
    • Provide Segments value(The segments parameter controls the number of line segments to use to approximate a quarter circle when creating rounded offsets)
    • Select End cap style from Round, Flat, Square (The end cap style parameter controls how line endings are handled in the buffer)
    • Provide Join Style from Round, Miter, Bevel (The join style parameter specifies whether round, miter or beveled joins should be used when offsetting corners in a line)
    • ProvideMiter Limit(The miter limit parameter is only applicable for miter join styles, and controls the maximum distance from the offset curve to use when creating a mitered join.)
    • Check Dissolve results
    • Click on Run

    Figure 95 - Buffer window for Point Layer

    • Temporary layer will be created and added to Layer panel with Buffered layer. Right click on the layer and save to destination folder.

    Figure 96 - Point data after Buffer

    • To create Buffer with attribute value, please follow the same procedure mentioned in page 68.

        1. Buffer – Polygon

      • Add Polygon Layer to Layers panel

      Figure 97 Sample Polygon layer before Buffer

      • Choose Vector → Geoprocessing tools → Buffer to open buffer window
      • Select Input Layer(Ex: AOI)
      • Provide Distance for creation of Buffer around the polygon data.
      • Provide Segments value(The segments parameter controls the number of line segments to use to approximate a quarter circle when creating rounded offsets)
      • Select End cap style from Round, Flat, Square (The end cap style parameter controls how line endings are handled in the buffer)
      • Provide Join Style from Round, Miter, Bevel (The join style parameter specifies whether round, miter or beveled joins should be used when offsetting corners in a line)
      • Provide Miter Limit(The miter limit parameter is only applicable for miter join styles, and controls the maximum distance from the offset curve to use when creating a mitered join.)
      • Check Dissolve results
      • Click on Run

      Figure 98 – Buffer window for Polygon layer

      • Temporary layer will be created and added to Layer panel with Buffered layer. Right click on the layer and save to destination folder.

      Figure 99 - Polygon layer after Buffer


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