Exploring the Contour Dialog Box - MapInfo_Pro_Advanced - 2023

Input

• Input File - Select a file to contour from the Input File drop-down list.
• Select Fields, Bands - If the selected input raster has multiple fields and bands, the Select Fields, Bands option allows you to choose either All Fields All Bands or a particular field for the processing.

  Select a specific field from the drop-down list, you can then choose the desired bands from that field. You can not select bands from different fields, because only one field can be selected at a time. Click the radio button against the field or check-box against the band that you want to select. By default All Fields All Bands option is selected for you.

Contour Intervals

This section contains the following:

• Contour Type - There are two types of contour that you can choose from the Contour Type drop-down list:
  1. Polyline - Generates contours polylines from the input raster.
  2. Region - Generates contours regions from the input raster.
• Method - There are two contour methods in the Method drop-down list:
  1. Fixed Intervals - The contour will be generated between the minimum and maximum values as specified in Intervals panel. You can preview the contour intervals under Interval List on the Contour dialog box.
  2. Custom Intervals - The contour will be generated for user defined intervals. You can define the contour intervals under Interval List on the Contour dialog box.

More Options

This section contains the following:

• Contour Region - This option defines the data extents in the input raster for which contouring will be performed. There are three options in this drop-down list:
  1. Full Data Extent - Denotes the complete extent of the input raster. Select this option if you want to generate contours for the entire raster extent.
  2. User Rectangle - Allows you to define rectangular bounds on the raster. Contours will be generated for the defined area only.
  3. Map Extent - Denotes the current map extent of the input raster. Select this option if you want to generate contours for the extent of current map window.
• Subdivide into regions - This option enables you to break the output contour tab file into smaller regions. Breaking into sub-regions creates multiple .TAB files, each representing a contour region.
• Region Width (Columns) - This option represents the number of columns for each sub-region.
• Region Height (Rows) - This option represents the number of rows for each sub-region.
• Discard small regions - Select this to dissolve smaller contour regions into the surrounding contour level and remove small islands from the output.
• Minimum region area - Specify threshold area for the contour regions. The Minimum region area box appears only when you select the Discard Small Regions check-box.

Intervals

In this section, you can contour intervals and assign colors to each contour level for both region and polyline contours, depending on the contour method selected. This section contains:

• Minimum - The minimum cell value that will be examined while contouring.
• Maximum - The maximum cell value that will be examined while contouring.
• Interval Method - Depending on the contour method selected, fixed or custom, the items in the drop-down list change.

  Fixed Interval

  Custom Intervals

  There are two interval methods: Use min/max as start end contour - Select this option to define the fixed contour levels between the values specified in Minimum and Maximum fields. In this option, the first level contour or base contour will start at the minimum value that you have specified. The subsequent contour levels will be created at an interval of the value specified in the Spacing field, till the maximum value is reached. For example, if the minimum value is -200, the maximum value is 200 and the contour spacing is 75, the first or base contour will be created at -200, then at an interval of 75 units. As a result, the output file will have contours at -200, -125, -50, 25, 100 and 175 levels. Use min/max to identify bounds - Select this option to define the fixed contour levels in order to define the contour bounds between the values specified in Minimum and Maximum fields. In this option, contour levels will define with constant Spacing in both up and down direction starting with 0 level. For example, if the minimum value is -200 and the maximum value is 200. You want to create contours at spacing of 75, the output Contour will be created at -150, -75, 0, 75, 150 levels.

  There are two interval methods: Number of intervals - Select this option to auto-generate contour interval by specified value in the Number field. Fixed Spacing - Select this option to auto-generate contour interval by specified value in the Spacing field. Note: The auto-generate contour interval are populated under Interval List in the Contour dialog box. You can modify number of intervals, interval spacing and interval style.

• Number - The number of contour intervals if Number of intervals is selected.
• Spacing - The number of contour intervals if Fixed spacing is selected.
• Resolution Level - Specifies the resolution level for contour generation. The Resolution level significantly affects the processing time for the operation. For example, as compared to resolution level = 0, expect an increase in processing time for resolution level = -1, and a decrease for resolution level = 1.
• Match Colors to Input - Select to style contours using colors from the source raster.

Output File

Select a location to save the contour TAB file to or type the name of the TAB file.