Using the Surface Analysis Tool - MapInfo_Pro_Advanced - 2023

To calculate the slope, aspect, or curvature of a raster:

1. On the RASTER tab, in the Operations group, click Raster Operations and then click Surface to open the Surface Analysis dialog box.
2. Select a raster file to calculate its slope or aspect or curvature from the Input File drop-down list.
3. Select a specific field from the Select Fields, Bands drop-down list, you can then choose the desired bands from that field.

   You can select multiple bands from any field, however, 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.

4. Select an option from the Compute drop-down list.
   • If you select Slope, you will have a slope grid as output.
   • If you select Aspect, you will have an aspect grid as output.
   • If you select Curvature, you will have curvature grid as output. Refer to Curvature for more details.
5. Depending on the selection,

   Select	Steps
   Slope	Calculate the output raster in degrees or percentage. Select either Degree or Percentage from the Slope Units drop-down list. Click More Options and type a value in the Vertical Scale Factor field. The vertical scale factor or z-scale property is used to adjust the units of measure for the data values in the raster when they are different to the x,y units of the input raster's coordinate system. The data values of the raster are multiplied by the z-scale factor before calculating the surface orientation to ensure that the slope or direction of the output surface is correct. If the x,y spatial units and z units are in the same units of measure, then the vertical scale factor is 1. This is the default. If the x,y spatial units and z units are in different units of measure, then the vertical scale factor needs to be set to the appropriate factor to convert them to the spatial units, or the output results will be incorrect. For example, if the z units of the raster are in feet but your x,y units are meters, then you would need to apply a vertical scale factor of 0.3048 in order to convert your z units from feet to meters (1 foot = 0.3048 meter).
   Aspect	Click More Options and type a value in the Vertical Scale Factor field. The vertical scale factor or z-scale property is used to adjust the units of measure for the data values in the raster when they are different to the x,y units of the input raster's coordinate system. The data values of the raster are multiplied by the z-scale factor before calculating the surface orientation to ensure that the slope or direction of the output surface is correct. If the x,y spatial units and z units are in the same units of measure, then the vertical scale factor is 1. This is the default. If the x,y spatial units and z units are in different units of measure, then the vertical scale factor needs to be set to the appropriate factor to convert them to the spatial units, or the output results will be incorrect. For example, if the z units of the raster are in feet but your x,y units are meters, then you would need to apply a vertical scale factor of 0.3048 in order to convert your z units from feet to meters (1 foot = 0.3048 meter).
   Curvature	Select the type of curvature to be used from the Curvature Type drop-down list. Click More Options and type a value in the Vertical Scale Factor field. The vertical scale factor or z-scale property is used to adjust the units of measure for the data values in the raster when they are different to the x,y units of the input raster's coordinate system. The data values of the raster are multiplied by the z-scale factor before calculating the surface orientation to ensure that the slope or direction of the output surface is correct. If the x,y spatial units and z units are in the same units of measure, then the vertical scale factor is 1. This is the default. If the x,y spatial units and z units are in different units of measure, then the vertical scale factor needs to be set to the appropriate factor to convert them to the spatial units, or the output results will be incorrect. For example, if the z units of the raster are in feet but your x,y units are meters, then you would need to apply a vertical scale factor of 0.3048 in order to convert your z units from feet to meters (1 foot = 0.3048 meter).

6. In the Output File box, enter a name for your output file. Click to browse and select the location in your computer to save the output file.
   1. Click Output Settings to specify the following. The output settings can be controlled by the values set in the Raster Preferences, however, you can overwrite those settings before executing the operation.
      • Display Output File - Select the check-box, if you want to open the output file in the Map window on completion of the operation. You can configure to make this the default behavior from the Raster Preferences dialog.
      • Compression Settings - If the file format to be saved is an MRR or TIFF, the compression settings options will appear. You can choose one from Data Balanced, Data Speed, Data Space or Advanced options as required.
      • Compression - Select a compression method and level. For more information, see Compression methods.
      • Encoding Type - Select a suitable Encoding Type for the data from the list. This drop-down list lets you select the default Encoding Type when saving a raster to MRR format. It enables you to compress the data when saving a raster to MRR format. Encoding Type is enabled only when the raster field type is Continuous and the compression method is lossless such as ZIP, LZMA or LZ4. The drop-down list contains the following:
        • None - No encoding.
        • Previous Column Linear - Linear estimation of the value from previous two columns.
        • Previous Column Value - Predicts the value from previous column.
7. Click Process to start creating a slope, aspect, or curvature grid and display the output on the map window.