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Creating Buffers in MapInfo Pro 64-bit

Products affected: MapInfo Pro™ 64-bit versions only

What is Buffer?

A type of proximity analysis where areas or zones of a given distance are generated around selected map objects (point, line or polygon). Buffers are user-defined or can be generated for a set of objects based on those objects' attribute values. Buffer zones are always represented as vector polygons enclosing other polygon, line or point features that is within the specified distance from the object.
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Buffer zone around point feature

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Buffer zone around line feature
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Buffer zone around polygon feature

 

What are basic parameters required to create buffer

  • Radius: The buffer radius is the distance between the object (or objects) and the border of the buffer polygon. The size can vary according to numerical values provided to create buffer.
  • Units: The numerical values have to be defined in map units according to the Coordinate Reference System (CRS) used with the data. If run in a projected coordinate system, distance calculated are in CRS units and if created in geographic coordinate system, distance are in meter.
  • Smoothness: The smoothness determines the resolution of the curves in the buffer polygon. The Greater smoothness factor/segments specified, a smoother curve is produced and lower value/a fewer segments make a more jagged curve.
  • Buffering with common/individual boundaries: Buffer zones can be generated to have common/individual boundaries for feature objects. In case of common boundaries, buffer zones have dissolved boundaries and there are no overlapping areas whereas in cases where individual buffer zones are created the overlapping areas may be created.
  • Buffer Width Distance: Buffer width distance can be calculated using Spherical/ Cartesian calculations distance methods.
    • Spherical: Spherical calculations are used for distance methods, which attempt to keep the measurement on the curved surface of the earth. The data is first converted to Latitude/Longitude and then a calculation is produced.Non-Earth data cannot use Spherical calculations, since the data cannot be converted to Latitude/Longitude.
    • Cartesian: Cartesian methods are used to perform calculations on Non-Earth data. Cartesian coordinates are a pair of numbers, (x, y), defining the position of a point in a two-dimensional space by its perpendicular projection onto two axes which are at right angles to each other.Cartesian calculations cannot be used for Latitude/Longitude data, which is not a flat projection.

How Buffer analysis helps?

The most frequently asked questions in geospatial world today is to know what is near me or how far something exists. For example, What is near me to eat? Where is the nearest Bank? How far is my building from coastline or from fire stations? To answer such questions on near or far, spatial analysis tool buffer plays an important role in extracting these information.

How to create Buffer using MapInfo Pro?

To create buffer objects using MapInfo Pro, On the SPATIAL tab, in the Edit group, Buffer, and click Buffer Objects to open the Buffer Objects dialog box.
Buffer objects are active only when a Map window is the active window and the Map window has an editable layer with at least one object selected in any layer.
To buffer objects:

Select the objects (specific/all objects) that you want to buffer
 
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Make sure there is an editable layer in the Map window. The output buffered objects will be placed in that layer.
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On the SPATIAL tab, in the Edit group, click Buffer. The Buffer Objects dialog box displays.

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Select appropriate buffer radius, segments per circle, distance type calculation to use, and buffer method as described.
  • Radius - The radius is the width of the buffer you want to create around the object you selected. The Value and the From Column radio buttons give you different ways to specify that width.
  • Value - Type a value into this field if the radius of the buffer you want to create is a specific distance. Examples might include 10 feet, 20 kilometers, 50 chains.
  • From Column - Select this radio button if the buffer you want to create is specified in a particular column or is to be calculated by an expression. Then select the column or choose Expression from the drop-down list. If you select Expression, the Expression dialog box displays. Specify the expression you want MapInfo Pro to use to calculate the buffer radius and click OK to return to the Buffer Objects dialog box.
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  • Units - Select the units for the buffer from this drop-down list. Options include: inches, links, feet, US Survey feet, yards, rods, chains, miles, nautical miles, millimeters, centimeters, meters, kilometers.
  • Smoothness - Type the number of segments per circle that determines the resolution of the curves in the buffer polygon. You can enter a number between 3 and 100. The default value is 12 segments per circle. If making adjustments, a value of 24 yields good results. The more segments you enter, the smoother the curve. The fewer segments, the more jagged the curve. More segments produce a smoother curve; fewer segments make a more jagged curve. Note: Creating a buffer is time consuming. The higher the smoothness (more segments), the longer it takes to create a buffer.
  • One buffer of all objects - Select this option to create one buffer for all of the objects you have selected. For example, if you are buffering Pennsylvania, New York and New Hampshire, one buffer will be created for all three of these objects.
  • One buffer for each object - Select this option to create one buffer for each object you have selected. For example, if you are buffering Pennsylvania, New York and New Hampshire, each object will have a separate buffer.
  • Buffer Width Distance using Spherical - Select this option if you want the buffer to take into account the curvature of the Earth. Using this method, MapInfo Pro converts the data to Latitude/Longitude and then creates a mathematical calculation of the buffer. You cannot use this method for non-Earth projections.
  • Buffer Width Distance using Cartesian - Select this option if you want the buffer to be calculated as if the map is on a flat plane. Cartesian coordinates are a pair of numbers, (x, y), defining the position of a point in a two-dimensional space by its perpendicular projection onto two axes which are at right angles to each other. If you are using a Latitude/Longitude projection, this option is disabled.
When you have completed your entries and selections in this dialog box, click the Next button. The standard Data Aggregation dialog box displays
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Highlight each of the columns to complete the fields in this dialog box.
  • No Change - Select this option to keep the value for the selected column in the target row unchanged. This option only displays when you combine objects into a target object.
  • Blank - Select this option to store blank values in the selected column(s). To store blank values in all displayed columns, select the No Data check box. Only choose the Blank option to blank out individual columns.
  • Value - Select this option to store the value that displays in the edit field in the new row. When you select this option, enter an appropriate value in the field.
  • No Data - Check this check box if you want no data aggregated to any column.
After setting the appropriate data aggregation parameters, click OK. MapInfo Pro calculates the buffer according to the parameters you set and creates the new objects in the editable layer. The original objects remain unchanged. Once MapInfo Pro has created the buffer region, it puts it in the editable layer.

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Set the style for Point and Buffer Zone for further analysis.


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Note: The maximum buffering resolution is 500 segments per circle.
When using this feature remember that the greater the value in the Smoothness field, the greater the demands you are placing on your system's RAM, on disk space, and on processing power.
 
UPDATED:  May 23, 2019