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MapInfo Monday: MapInfo Dispersed Groups Font

  • 1.  MapInfo Monday: MapInfo Dispersed Groups Font

    Employee
    Posted 06-19-2023 04:46
    Edited by Peter Møller 06-19-2023 04:48

    Happy #MapInfoMonday!

    It is in fact not that rare to have multiple points at the same location. For an insurance company, it could be the types of insurance that exist at a given address. For single-family homes, that may be up to a handful. For a telco, it could be the types of technology used at a given site (2G, 3G, 4G, 5G, etc), and for crime investigators, it could be the types of crimes taking place. These are just a few examples, and I'm sure you can quickly come up with more.

    In this specific example, I have taken on the hat of a crime analyst looking to find patterns of crime types happening along with burglaries.

    I have a single table with the crimes in a given area related to burglary. Let me stress that these data points have been invented by me.

    In this map, you can see the crimes spread across an area. There were 108 burglaries and three typical other crimes happened at the same location at the same time. But the map doesn't tell the entire truth. Why not?

    Well, the problem is that these points all overlap. They have been geocoded to the same address and have so the same coordinate assigned to them. This means that for each point, I can only see one of the four crime types that might have taken place.
    There is a simple way to get around this issue of having multiple points drawn on top of each other. We can use the MapInfo Dispersed Groups Font. This font consists of multiple fonts that can be used together. Each only makes up a part of the full symbol, typically half or a fourth of the full symbol. This means that I can use four different symbols for each value and so the resulting symbol will have only one part, two parts, three parts, or in rare cases all four parts.
    In the image below, you can see the symbols of the MapInfo Dispersed Font. I have grouped the symbols so you can see how you can combine these to make up a full symbol. These groups consist of 2, 3, 4, or 16 symbols.
    I have used a thematic map and need to modify this to use the MapInfo Dispersed Groups Font. I click on the thumbnail next to the Thematic Map to access the Modify Thematic Map dialog.
    In the Modify Thematic Map dialog, I click on Styles... to change the styles.
    I now need to modify each symbol. I double-click on the Individual Value one at a time to access the Symbol Style dialog. First, I have to change the Font to MapInfo Dispersed Groups.
    Now, I can choose four different symbols that all below to the same group. You can see the different groups in the image above. In my example, I choose the symbols in E3 to H3 as they together make up a full symbol.
    When you have selected the symbol from the MapInfo Dispersed Groups font, you can click OK to get back to the Cusomize Individual Styles dialog.
    When you have selected a symbol from the MapInfo Dispersed Groups font for all values, you end up with a dialog like this. Notice how the symbols no longer align vertically as they each only make up part of the full symbol. Click OK to modify the thematic map.
    In the map, it now becomes more clear which incidents had multiple crimes as you can see below.
    In this map where I have only taken out a part, it's more clear. You can of course also make the font even bigger through your thematic map.
    In my example, I have used a thematic map. You can of course also use this if you have say four layers where you know some of the points overlap. You just use a group of symbols from the MapInfo Dispersed Groups font for each layer override.

    Fast Symbol Rendering

    I also want to make you aware of a feature in MapInfo Pro that may result in an issue with your map when points tend to lie in the same location: Fast Symbol Rendering. Fast Symbol Rendering was implemented to speed up the rendering of a map with many points. If you turn on Fast Symbol Rendering, MapInfo Pro will only render a symbol once at each pixel. This works very well for datasets where you just want to see how points are spread and where points are all rendered with the same style.
    In our example, it would end up with only one symbol at each location even though some of these locations should have 4.
    Make sure to disable Fast Symbol Rendering under Output Preference when you are working with data like this in your map.
    This article was heavily inspired by a user question and by this Support article: Understanding MapInfo Professional and use of the Dispersed Group Symbol Set



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