Attribute Errors: Missing and Incorrect Attributes and Solutions (Especially for GATE-Geospatial 2022)

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Attribute errors generally more difficult to detect because the GIS does not know which attributes are correct and which are not. There are two types of attribute errors:

This Diagram Shows Types of Attribute Errors

Missing Attributes

Missing attributes are the only attribute errors that are detectable without direct comparison to the input document. In raster graphics, this occurs when whole rows or columns or portions of rows or columns are missing in map. E. g. plot all polygons and color them according to a certain attribute, if color is missing, attribute is missing. A simple way to avoid this type of error is to display the text equivalent of the attribute prior to completing the input.

Effects

In raster, if you miss a complete row of data, or more than one row of data, your map will appear shorter than it should. Missing attribute values in vector GIS are commonly caused by simply not including anything in the attribute tables for individual points, lines, or polygons.

Diagram Shows Missing Attributes Error

Incorrect Attribute Values

Incorrect attribute values errors are more difficult to detect. In raster GIS, when they occur as individual cases, they are most often caused by typing errors. When entirely incorrect attributes occur for large areas, they are most likely a result of inputting the wrong attribute value, either through digitizing or a block encoding method. Incorrect attributes are often more difficult to identify in vector than in raster because the vector case generally calls for intimate familiarity with the source map and its attributes and attribute patterns before these can be compared to the digital version.

Solution

One method is to plot all polygons and color them according to a certain attribute, if only one polygon has a certain attribute and there should be other, it may stick out, in general, involves direct comparison with source material.

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