GDAL Virtual Raster (beta)
Open BetabetaVRT, एक रास्टर डेटासेट का GDAL का XML विवरण है। हम VRT को एक रेंडर किए गए GeoTIFF के साथ एक ZIP (map.vrt.zip) में पैक करते हैं — अन्यथा gdalinfo/gdal_translate "map.tif not found" त्रुटि के साथ विफल हो जाते हैं। Beta: फ़िलहाल बिना ओवरव्यू के एकल बैंड-सेट।
मुख्य विशेषताएँ
VRT प्रारूप के बारे में
VRT is a service format of GDAL: an XML file that contains no pixels but describes where they lie and how to read them. That is the usual way to stitch mosaics and redefine referencing without copying gigabytes of raster.
We hand over the VRT together with the raster itself: the map.vrt.zip archive holds the XML description and the rendered map as a GeoTIFF. That was done deliberately — a lone .vrt would refer to a file you do not have, and gdalinfo simply would not open it.
The XML records the WGS84 coordinate system, the georeferencing (corner coordinates and pixel size) and three RGB bands, each pointing at the corresponding band of the GeoTIFF. The format is in beta status: it is one set of bands with no overview pyramids, and the raster itself is a flattened picture of the map rather than vector layers.
VRT फ़ाइलें कौन सा प्रोग्राम खोलता है
निम्नलिखित प्रोग्राम और अनुप्रयोग OSM2CDR से निर्यात की गई GDAL Virtual Raster (beta) (.vrt.zip) फ़ाइलों को खोल, संपादित और उनके साथ काम कर सकते हैं:
Format specifications
- Open standard
- 2D only
- Lossless (no quality loss)
- No attributes
- Output: 1 file
- GDAL Virtual Raster (.vrt). XML descriptor referencing source rasters; lazy mosaicing without copying pixels.
VRT मानचित्रों का उपयोग कौन करता है
VRT कैसे निर्यात करें
निर्यात के बाद कैसे खोलें
- Unpacking is a mandatory first step: map.vrt and map.tif must lie next to each other in the same folder, since the reference inside the XML is relative.
- GDAL — gdalinfo map.vrt will show the size, the referencing and the bands; gdal_translate will convert the set into GeoTIFF, PNG or COG.
- QGIS — Layer → Add Raster Layer and pick map.vrt; the layer will land in its place by coordinates.
- A mosaic — your own .vrt over several rasters is assembled with gdalbuildvrt out.vrt tile1.tif tile2.tif, if the map has to be stitched with other data.
- Editing by hand — VRT is plain XML: the path to the raster, the referencing and the band descriptions can be fixed in a text editor.
VRT में लोकप्रिय मानचित्र
GDAL Virtual Raster (beta) मानचित्र निर्यात प्राप्त करें
OpenStreetMap से पेशेवर VRT मानचित्र डाउनलोड करें. तत्काल जनरेशन, कोई भी क्षेत्र.