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MapInfo Monday: Enrich a Point Dataset with Values from a Raster Grid

  • 1.  MapInfo Monday: Enrich a Point Dataset with Values from a Raster Grid

    Posted 08-08-2022 09:21
    Happy #MapInfoMonday

    We will stay in the world of raster data in this week's article but we will sprinkle it with the use of vector data.

    It is often very useful to be able to combine the use of raster and data in an analysis or workflow in MapInfo Pro. In this specific example, I will show you how you can enrich a vector dataset with values from a raster dataset.​

    The use case for this could be an engineer working for a telecommunications company where she needs to understand the performance of their network across an area and report this back through her organization. It could also be a local authority looking to understand the elevation at specific locations to assess the risk of flooding.

    In both these examples, it can be useful to get the value from a raster grid written to a point dataset.

    Let's look at how this can be done with MapInfo Pro.

    In our example, we have a coverage dataset created from a drivetest. This shows how well the network performs in a given area.

    We also have a vector grid in the form of points spread evenly across the area of our network. For reporting purposes, we need to understand how well the network performs at these specific locations. Luckily MapInfo Pro comes with a method for enriching point data with values from one or multiple raster grids. This method is called Point Inspection.

    With the two datasets open in MapInfo Pro access Point Inspection from the Raster Operations gallery on the Raster tab.

    The Point Inspection panel opens and will typically get docked to the right side of the MapInfo Pro window.

    First, you need to select the Input File. This is the raster grid you want to read values from. If you want, you can read from multiple raster grids at the same time. That could for example be useful if you need to enrich the points with performance numbers from different times, maybe from raster grids representing the coverage over the last 3 months so that you can see how the performance is improving, or not.

    In our example, I just check the one raster grid I currently have open.

    Now you need to configure the point dataset to be used. I select the table with points. From the Output Mode, I select the option to Edit input tab file as I already have a column where I can write the values to. You can also select the option to Create a new table and during this process add the additional column(s).

    I also check the two options: Specify null-cell value and Specify no-cell value. This gives me the option to control what value is written to the points that lie in an area where the value is Null or outside of the extent of the raster grid. In my example, I specify to use the same value for these two cases.

    Finally, I have also specified what column in the point table to write the values to. If your raster grid had multiple Fields and/or Bands, you would be able to specify which to use.

    And if you have selected multiple Input Files, you would be able to specify the settings for each in the list, say what column to write the values to and the null-cell and no-cell values.

    If you had selected the option to Create a new table you would also be asked to specify a name for this new table.

    Hit Process to run the Point Inspection process.

    Once the process has finished, the resulting table will be shown in a browser window where you can see the values inserted into the selected column.

    In this final image, I have added a thematic layer to the point table to show the values that have been assigned to the points. You can see how the size and the colors of the points relate nicely to the underlying raster grid values.

    I hope you found the combination of raster grid and vector datasets interesting. If you already are using this in your daily work, I would love to hear more about the use case. Please write a small comment and share this with me and the community.

    Peter Horsbøll Møller
    Principal Presales Consultant | Distinguished Engineer
    Precisely | Trust in Data