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  • 1.  What is the best way to find out the area of a lot in MapInfo Pro

    Posted 09-20-2017 02:06
      |   view attached

    ?I need to find out the area of some properties lots in MapInfo Pro. I double click on a lot and the Region Object Dialogue Box Appears which tells me the Total area of the lot I just click on. It tells me in Sq Km (Spherical). What does spherical mean? And is this the most accurate way to find out an area in MapInfo?See Attachment



  • 2.  RE: What is the best way to find out the area of a lot in MapInfo Pro

    Employee
    Posted 09-20-2017 03:07

    If you need to check the area of a lot of polygons, I would recommend that you create a label that shows the area of all your lots.

    Such an expression could be as basic as this: Area(OBJ, "sq m") + " sq m"

    This will show the area in square meters and add the text " sq m" to the area in order to makesure you know the unit used.

    As for Spherical, this is one way of calculating the areas or lengths in MapInfo Pro. I only recommend the Spherical calculation for lat/lon coordinate system.

    If you are using a projected coordinate system, I would recommend that you use the Cartesian calculation method in stead.

    You can specify this in your label expression, too: CartesianArea(OBJ, "sq m") + " sq m"

    Using the like this might not make the area look very nice as it might have many decimals etc. So to improve the expression you can format the number value and also round the area to for example two decimals: FormatNumber$(Round(CartesianArea(OBJ, "sq m"), 0.01)) + " sq m"?



  • 3.  RE: What is the best way to find out the area of a lot in MapInfo Pro

    Posted 10-11-2017 12:03

    Hi Jemima

    Spherical usually relates to projections that are in Long/Lat and designed to take into account the earth's curvature. The other option is Cartesian?, when you have a projection that has "flattened" the earth and likely to use x and y co-ordinates from a designated origin e.g. British or Irish Grid (you can't do this for huge areas/countries).

    You should use and set your projections in your Options >Preferences so that they become your default table and session projections. You can alter session projections at any time under the Map Options. You will get different results for spherical and Cartesian, so it is important that you apply the correct one to go with your projection.

    What mapping are you using?