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MapInfo Monday: Merging multiple grid files into one

  • 1.  MapInfo Monday: Merging multiple grid files into one

    Posted 03-22-2021 12:17

    Happy #MapInfoMonday,

    Today we will​ look at another feature from MapInfo Pro Advanced that is useful when downloading multiple raster files from a data provider at looking to work with these in MapInfo Pro.

    The Finnish National Land Survey has just published a new elevation model covering Finland with a 2 by 2 meter resolution. The article here is in Finnish or Swedish, sorry!

    You can get to the data through the File Download Service site. At the top of the page, you can switch to English if you prefer that to Finnish or Swedish. Using a map interface, you can select the map tiles, you want to download, and after a short while, you will be sent an email to a page where you can download the files. I downloaded 20 map tiles to use in MapInfo Pro.

    Opening the Map Tiles into MapInfo Pro

    Once you have downloaded the files, you can open them into MapInfo Pro using the Open dialog. Switch the File Type dropdown to Raster and you can see and select all the TIFF files you downloaded.

    Once they have been opened into a map window in MapInfo Pro, you quickly notice a few things.

    You have multiple rasters appearing in the Explorer window, one for each raster file. In the map window, the colors seem to change for each map tile that you opened. That's because the color palette is spread according to the minimum and maximum value in each raster grid.

    And if you want to start analyzing these rasters, you will have to deal with multiple files each time. All these issues give you a good reason to merge the individual raster files into a single file.

    Merging multiple raster files into one

    Luckily, there is an easy way to merge all these files into one without even opening them into MapInfo Pro. From the Raster tab, click on the Raster Operations dropdown and select the Merge option.

    In the Merge panel that now has appeared, click the Browse button in the top right corner which will open a new dialog where you can select the raster files that you want to merge.

    When you have selected the files to merge and have clicked the OK button, the files are loaded into the Merge panel in the Rasters to Merge list.

    In the Output area, you can specify the name and location of the Output File. You can also specify the output file type. By default, it will be of type MRR, MapInfo Multi-Resolution Raster.

    Just before you click Process to merge the files, I want to highlight another useful feature. In some cases, you might have data for a very large area but you only need to merge data for a smaller area. To limit the area of interest, you can use the extent of your current map window or a polygon in a table. Using the Merge Region, you can select the area of interest to you.

    Now it is time to merge the files. Hit the Process button to do so. MapInfo Pro Advanced starts a background task to process the data. You can see the progress of this process in the Task window inside MapInfo Pro. In the image below, the Task window can be seen on the lower left side. While the process is running, you can still continue to use MapInfo Pro for other tasks.

    Once the process has finished, the resulting raster grid will be opened into a map window in MapInfo Pro and you can start using it for your work.

    Stay tuned for another article next week!

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

  • 2.  RE: MapInfo Monday: Merging multiple grid files into one

    Posted 03-23-2021 11:41
    Edited by John Ievers 03-23-2021 11:41
    This also works very well with merging raster mapping into one MRR file for improved handling and superb performance. Here is OS 1:50,000 scale mapping of GB - 805 tiles merged into one.

    John Ievers
    CDR Group
    Hope Valley, United Kingdom