GDAL Scheme bindings for Guile programming language.
This library allows you to perform the following tasks:
- Open a raster file for reading and writing
- Access metadata of raster files
- Compute statistics of raster files
- Access layers of raster dataset
- Helper functions, providing idiomatic Scheme interface to the GDAL APIs
- TODO: OGR support
Read/write raster files using GDAL binding functions or helper functions
(use-modules (gdal))
(use-modules (gdal extension))
(use-modules (rnrs bytevectors))
;; initialize GDAL by registering GDAL drivers
(all-register)
;; read raster dataset using binding functions
(let* ((dataset (open-dataset "raster-small.txt" GA_READONLY))
(h-band (get-raster-band dataset 1))
(x-size (get-raster-band-x-size h-band))
(y-size (get-raster-band-y-size h-band))
(size (* x-size y-size))
(bv (make-s32vector size)))
(begin
(raster-io h-band GF_READ 0 0 x-size y-size bv x-size y-size GDT_INT32 0 0)
(for-each (lambda (i) (format #t "~a " (s32vector-ref bv i)))
(iota size))))
(newline)
;; or read raster dataset using helper functions in the extension module
;; providing more convenient way
(let* ((dataset (open-dataset "raster-small.txt" GA_READONLY))
(h-band (get-raster-band dataset 1))
(buf (make-buffer-all-from-band h-band GDT_INT32)))
(for-each-pixel (lambda (p) (format #t "~a " p)) buf))
;; transform pixels using map-pixel function, returning a new binary buffer
;; of type INT16 with 1 for pixels greater than 0, and 0 otherwise.
;; use write-buffer-to-file to save the buffer into the disk in GeoTIFF format.
(let* ((dataset (open-dataset "raster-small.txt" GA_READONLY))
(h-band (get-raster-band dataset 1))
(buf (make-buffer-all-from-band h-band GDT_INT32)))
(begin
(define new-buf (map-pixel (lambda (p) (if (> p 0) 1 0))
buf #:buf-type GDT_INT16))
(write-buffer-to-file new-buf GDN_GTIFF
"new-raster-small.tif" #:no-data -1)))
See examples folder for more code samples.