5、GeoTrellis-读取栅格文件

读取单波段的栅格

import geotrellis.raster.io.geotiff.SinglebandGeoTiff import geotrellis.raster.io.geotiff.reader.GeoTiffReader object demo4 { def main(args:Array[String]): Unit = { val geoTiff: SinglebandGeoTiff = GeoTiffReader.readSingleband("/Users/mocker/Documents/test/jpeg-test-small.tif"); println(geoTiff) } }

读取多波段栅格

mport geotrellis.raster.io.geotiff.{MultibandGeoTiff, SinglebandGeoTiff} import geotrellis.raster.io.geotiff.reader.GeoTiffReader object demo4 { def main(args:Array[String]): Unit = { val geoTiff: MultibandGeoTiff = GeoTiffReader.readMultiband("/Users/mocker/Documents/test/jpeg-test-small.tif"); println(geoTiff) }

使用流读取栅格

通过流读取的tif，单个小文件可以完整的读取，大文件则Java虚拟机会内存溢出崩溃，大文件和小文件都有一个共同之处，所选的区域越小读取的速度也快，所以对栅格读取区域的范围要严格的控制，避免程序崩溃。

使用流读取指定区域的栅格数据

import geotrellis.raster.io.geotiff.{MultibandGeoTiff, SinglebandGeoTiff} import geotrellis.raster.io.geotiff.reader.GeoTiffReader import geotrellis.vector.Extent object demo5 { def main(args:Array[String]): Unit = { val path: String = "/Volumes/Samsung_T5/1.tif"; //指定区域 val e: Extent = Extent(361557.21354599966, 3374714.92064873, 361559.67652580043, 3379714.2052475177); //单波段读取 SinglebandGeoTiff(path, e) GeoTiffReader.readSingleband(path, e) //多波段读取 MultibandGeoTiff(path, e) GeoTiffReader.readMultiband(path, e) //单波段读取 SinglebandGeoTiff(path, Some(e)) GeoTiffReader.readSingleband(path, Some(e)) //多波段读取 MultibandGeoTiff(path, Some(e)) GeoTiffReader.readMultiband(path, Some(e)) }

使用流读取已加载的栅格进行裁剪

通过裁剪读取已经加载的tif数据，使用此方法不需要去读取文件，直接就可以访问数据，先加载文件再进行裁剪。

import geotrellis.raster.io.geotiff.reader.GeoTiffReader import geotrellis.raster.io.geotiff.{MultibandGeoTiff, SinglebandGeoTiff} import geotrellis.vector.Extent object demo6 { def main(args:Array[String]): Unit = { val path: String = "/Volumes/Samsung_T5/1.tif"; //指定区域 val e: Extent = Extent(361557.21354599966, 3374714.92064873, 361559.67652580043, 3379714.2052475177); //单波段读取裁剪 SinglebandGeoTiff.streaming(path).crop(e) println(SinglebandGeoTiff.streaming(path).crop(e)) GeoTiffReader.readSingleband(path, true).crop(e) //多波段读取裁剪 MultibandGeoTiff.streaming(path).crop(e) GeoTiffReader.readMultiband(path,true).crop(e) } }

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