2.3 KiB
GDAL Raster GeoTIFF Workflow
Build Tools: CMake/Ninja
OS: Linux
For installing GDAL:
sudo apt-get install python3.6-dev
sudo add-apt-repository ppa:ubuntugis/ppa && sudo apt update
sudo apt-get install gdal-bin
sudo apt-get install libgdal-dev
Dependencies:
PNG: sudo apt-get install libpng-dev
PCRE: sudo apt-get install libpcre3 libpcre3-dev
PROJ: sudo apt-get install libproj-dev
Initializing GDAL submodule:
git submodule add https://github.com/OSGeo/gdal/tree/master/gdal
Building GDAL statically
GNUmakefile from gdal/gdal can handle building the static library.
cd gdal/gdal && make static-lib
cd ../.. && mkdir lib
cp gdal/gdal/libgdal.a lib/
OBS: The file is huge! It may take a while.
For testing:
mkdir build && cd build
cmake .. -G Ninja
ninja
./raster <your_absolute_tiff_file_path>
About the project
GDAL is a translator library for raster and vector geospatial data format. The project consist in rastering a GeoTIFF file format using GDAL functionalities and sandboxed methods.
Implementation
Sandboxing...
The purpose of sandboxing is to limit the permissions
and capabilities of library’s methods, in order to
secure the usage of them. After obtaining the sandbox,
the functions will be called through an Sandbox API
(being called api in the current test) and so, the
operations, system calls or namspaces access may be
controlled.
Raster process...
From gdal.h header useful methods are added to sapi
library builded with CMake.
One .tiff file is manipulated with GDALOpen
functionality, which extracts a pointer to the data set
containg a list of raster bands, all pertaining to the
same area.
Metadata, a coordinate system, a georeferencing
transform, size of raster and various other information
are kept into the data set that corresponds to the image.
To create an array containing the image information, the
dimentions needed are extracted using some specific
GDAL(X/Y)Size functions applied to the block.
GDALRasterBand function takes care of data type conversion, one more step following: placing the
converted data (with RasterIO method) into the created
and well allocated structure.