Introduction
Geospatial data can be represented in various file formats, each serving specific use cases. Some examples are shapefile (.shp), GeoJSON, and KML file formats. In using Meridia Verify portal, multiple file formats are compatible for geospatial data submission, shown in the picture below.
Understanding these formats is crucial for compatible and accurate use of not only Meridia Verify, but also other geospatial tools related to spatial analysis and data processing.
This tutorial introduces the steps on how to convert your file into another file format using QGIS. Two common file formats in geospatial applications that are not compatible yet with Meridia Verify are introduced:
GPX (GPS Exchange Format): A widely used format for storing GPS data, including waypoints, routes, and tracks.
DXF (Drawing Exchange Format): A CAD-based format developed by Autodesk, commonly used for vector-based design files.
Before proceeding with this tutorial, ensure that QGIS is installed on your machine. If not, refer to QGIS installation guide. This tutorial is created using MacOS, but users on other operating systems should be able to follow along without major differences.
Import GPX Data in QGIS
To import GPX data into QGIS, click on Layer menu > Add Layer > Add GPX Layer.
In the Data Source Manager, browse to your GPX file location.
Select the GPX file and click Open.
Choose the feature types to load (Waypoints, Routes, or Tracks) and click OK.
Click Add.
The GPX data will now appear on the Layers panel and on the map view.
Convert GPX Lines to Polygon
To convert GPX line features into polygons:
Open Processing Toolbox.
Search for Lines to Polygon, then double-click on Lines to Polygon to open the tool window.
Select the Track layer (consisting of line string data from GPX) as the Input Layer.
Click Run to start the process.
A new polygon layer will be generated and displayed in QGIS.
Export the Resulted Polygon Data
To export the newly-created polygon, right-click on the resulting polygon layer > Export > Save Feature As… .
On the Export window, set up the vector layer configuration.
Select Shapefile (.SHP) as the export format.
Choose a directory and filename for the output file.
Click OK to complete the export. You can find the exported file in the chosen directory.
Import DXF Data in QGIS
To import DXF data into QGIS, click on Layer menu > Add Layer > Add Vector Layer.
In the pop up window, choose the data to add to QGIS.
Browse to the DXF file location and select it.
Choose the Feature Types (Points, Lines, or Polygons) to be imported.
Click Add Layers.
Click Add.
The DXF data will now be displayed on the map view and listed in the Layers panel. You may notice that the imported data has a warning attached regarding the missing coordinate reference system (CRS).
To solve this issue, simply set the data into the QGIS Project CRS by right-clicking on the data > Layer CRS > Set to the preferred CRS.
To convert the imported linestring to polygon, repeat the previously mentioned steps.
Export DXF Data as GeoJSON
To export the newly-created polygon, right-click on the resulting polygon layer > Export > Save Feature As… .
On the Export window, set up the vector layer configuration.
Select GeoJSON as the export format.
Choose a directory and filename for the output file.
Click OK to complete the export. You can find the exported file in the chosen directory.
After exporting the GPX and DXF data into Shapefile (.SHP) and GeoJSON (.geojson) formats, respectively, navigate to the directory where the files were saved. Ensure that all expected files appear and can be reloaded into QGIS for further analysis.
Conclusion
Choosing the right file format is crucial for maintaining the compatibility and interoperability of your dataset to any kind of applications that might use the data. By following this tutorial, you have successfully imported GPX and DXF data into QGIS, processed them, and exported them into suitable formats for Meridia Verify or other applications for any further processing.
We encourage users to use this tutorial for different scenarios to get familiar with QGIS and with the process itself which will help you in other geospatial data engineering issues and problems in the future.
Please refer to additional resource below to get more information regarding this tutorial.