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MapInfo Monday: Finding the Perfect Spot

  • 1.  MapInfo Monday: Finding the Perfect Spot

    Posted 11-28-2022 03:36
    Happy #MapInfoMonday!

    In today's post, we will look at how you can use MapInfo Pro to locate the perfect spot by ruling out areas that don't meet your criteria.

    For example, I will look for locations to put up windmills. Renewal energy is becoming even more critical these days so finding the possible locations is vital for growing this resource. In my example, I will only use a few of the datasets that are needed in locating the possible spots. You can of course add more sources in order to finetune this method.

    Data Sources

    I'm using a small subset of the data sources in order to start narrowing down my area to areas that could be suitable for setting up windmills.

    I'm using railroads, highways, streets, and addresses. There are regulations in place to prevent the building of windmills within a certain distance of these "structures" in the countryside. In the map below, you can see these elements.

    Typically, the distance isn't fixed but depends on the height of the windmills. In Denmark for example, there is a rule that the distance to the nearest address, or residence, must be 4 times the height of the windmill.

    In my example, I'm therefore using a distance of 600 meters to the addresses to calculate locations for 150-meter windmills.

    The Process

    The process is straightforward and could also be automated with a MapBasic application or a small script. First, you create buffers of a given size around the input layers. Next, you erase the target area with these buffers to remove the areas that do not meet your condition (of being outside of the buffer). Finally, you can disaggregate the remaining area of interest to see the size of the individual polygons.

    Let's start by buffering all the input layers.

    From the Buffer dropdown on the Spatial tab, I select Buffer Table.

    Select the input layer, here Rail_Road, and select <New> to create a new table for the buffer. In my example, I have chosen to create a buffer table for each input layer. You can also create all the buffers in one table if you prefer.

    I use the New Table dialog to Add the new table to the Current Mapper and create the table structure using an existing table. The latter is especially useful for the remaining tables as they will have the same structure as the first table I create. For the first table, I use the input table. For the remaining tables, I use the Buffer Rail Roads table instead.

    I use a simple structure with an ID and a buffer width. I could also have chosen to add a name column to hold the name of the input layer in case I save all by buffers to one table.

    I also specify where to save this new table and now I'm ready to create the buffers around the selected input layer.

    I specify a buffer of 300 meters. You will need to identify the different distances yourself as they will vary from layer to layer, and probably also from country to country. I have only verified the distance to the addresses. The other distances I'm using are guesses from my side.

    Notice that I have chosen to create a single buffer for all objects in the input layer. That's because I don't need to individual buffers.

    In the dialog Data Aggregation, I set the values to be inserted into the buffer tables. I give each input layer an individual ID and specify the buffer size used.

    Below you can see the buffer around the rail roads.

    We repeat this process for the highways

    And the streets. Note that I have switched to a full-colored style for the buffers but set them to be 50% transparent.

    And finally, the addresses.

    In the next step, I will erase the land polygon where it overlaps the buffers around the input layers. I make the land polygon layer editable, select it and set it as the target.

    I then select the Railroad buffer and from the Spatial tab, I select Erase from the Erase dropdown. I repeat this for the other buffer layers. If you have saved all your buffers into one layer, you only need to do this once.

    You can now start seeing through the land polygon where the overlapping area has been erased around the railroads and the highways.

    And after having erased all the overlapping areas, I end up with this result. The dark green polygons are the possible locations.

    I select all the land polygon records and use Disaggregate to split the polygons into individual polygons. Until now they may have been connected if they all derive from one input land polygon record. After disaggregating the polygons, I can label the polygons and see their actual size.

    I hope this gave you a good idea of how you can use MapInfo Pro to determine possible locations. In my example it was windmills, but it can be anything where the distance to other features plays a role in the decision.

    Also, note that I have only used a logic where my area must be outside of the resulting buffers. But in some cases, you may be looking for the area inside the buffers. That could be within a given distance of schools, shopping, highway exists, and more. In those cases, you can use Erase Outside to keep the area inside your buffer.

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