Formato de Dados Suportados¶
QField supports a wide variety of formats via QGIS data providers and GDAL. This page offers a non-exhaustive list of supported data formats.
| Formato de Data | Suporte | Notas |
|---|---|---|
| Spatialite | ||
| Geopackage | ||
| WMS | ||
| WFS | ||
| WFS-T | ||
| Postgis | ||
| MBTiles | ||
| Shapefile | ||
| Tiff | ||
| JPEG2000 | ||
| WEBP | ||
| ECW | Licença de utilização restrita. | |
| MrSID | Licença de utilização restrita. |
If you don't find your favorite data format on this table, please check if it works and adapt the list above to share your findings. If it does not work, please open an issue. We will be happy to help you with the implementation.
Dados raster¶
Os dados raster podem se tornar muito grandes rapidamente, quando trabalhamos com dados descompactados, os tiff são geralmente de vários Gb. Em dispositivos móveis, em especial é ineficiente.
Utilizar COG (Cloud Optimized GeoTIFF)¶
The Cloud Optimized Geotiff (COG) format will offer best user experience for offline basemaps. Combined with JPEG compression, it will reduce the raster size.
Os seguintes comandos vão converter um ficheiro com o nome raster.tif para um ficheiro COG raster_cog.tif com compressão JPEG.
gdal_translate raster.tif raster_cog.tif -of COG -co BLOCKSIZE=512 -co COMPRESS=JPEG -co QUALITY=75 -co BIGTIFF=YES
Exemplos avançados com o COG¶
If you have several files to assemble, first, you need to create a VRT file with QGIS or through following commands to index all TIF files inside a directory. Make sure you adjust EPSG:2056 to your desired CRS.
gdalbuildvrt raster_mosaic.vrt TIF_Directory/*.tif -addalpha -hidenodata -a_srs EPSG:2056
Then convert the VRT file to COG.
gdal_translate raster_mosaic.vrt raster_cog.tif -of COG -co BLOCKSIZE=512 -co COMPRESS=JPEG -co QUALITY=75 -co BIGTIFF=YES
If the data quality of the raster data is too low, adjust the compression level and set QUALITY=85.
Alguns parâmetros extra podem ser definidos :
a_srscan also be used in gdal_translate command when the CRS is not defined in the source raster dataset.OVERVIEW_RESAMPLINGoffer different renderer when zooming out. The default value is NEAREST but you can try also BILINEAR or AVERAGE.NUM_THREADSwill help you to balance between use all your CPU resources or only part. Set ALL_CPUS or define the number of thread you want to use.
Combinando todos os parâmetros extra, na linha de comandos, pode ser algo como isto :
gdal_translate raster.tif raster_cog.tif -a_srs EPSG:2056 -of COG -co BLOCKSIZE=512 -co OVERVIEW_RESAMPLING=BILINEAR -co COMPRESS=JPEG -co QUALITY=75 -co NUM_THREADS=6 -co BIGTIFF=YES