notes for GDAL hacking - Githubissues

mdsumner commented 2 years ago

how to rebase https://adamj.eu/tech/2022/03/25/how-to-squash-and-rebase-a-git-branch/

git checkout master
git pull
git checkout <new-feature>
git rebase --keep-base -i master  ## fixup all the dross (f on lines below first)
git rebase -i master

Getting this down to much tighter

git clone https;//github.com/osgeo/gdal.git

## get a specific PR branch
#git remote add rouault https://github.com/rouault/gdal
#git fetch rouault
#git checkout <...>

## sudo usermod -aG docker $USER
## fire up docker for gdal-deps, so we can build with whatever PR 
docker run -it \
    -v $(pwd):/gdal:rw \
    ghcr.io/osgeo/gdal-deps:ubuntu20.04-master
cd gdal
mkdir build
cd build
../.github/workflows/ubuntu_20.04/build.sh
make install

to build from source do

 sudo python3.10 -m pip install -r ./doc/requirements.txt
 sudo python3.10 -m pip install -r ./autotest/requirements.txt

cmake .. -DCMAKE_INSTALL_PREFIX=/usr  -DCMAKE_UNITY_BUILD=ON  -DCMAKE_BUILD_TYPE=Release -DPython_LOOKUP_VERSION=3.10.12

sudo cmake --build . --parallel 31  --target install

to lint and test

pre-commit run --all-files

pytest autotest/gcore/vrt_read.py -k test_vrt_protocol

with rocker:

docker build . -f dockerfiles/geospatial-dev-osgeo_4.3.1.Dockerfile  -t install-osgeo.gdal
docker run --rm -ti install-osgeo.gdal bash

OLD NOTES BELOW

To check out and build GDAL from source, as ubuntu user

GDAL Build hints

https://gdal.org/build_hints.html

My notes

first PROJ (Note that 8.2 is still autotools, cmake required as of version 9.0 - I'll update)

git clone https://github.com/osgeo/proj
cd proj
git checkout 8.2
./autogen.sh
./configure --prefix=$HOME

make  ## I have 'MAKEFLAGS -j[n]' env set
make install

now GDAL, with new cmake

#sudo apt-get install python3-dev
#git clone https://github.com/osgeo/gdal
#cd gdal
#mkdir build
# cd build

cmake .. -DCMAKE_INSTALL_PREFIX=$HOME
cmake --build . --parallel 26  
cmake --build . --target install

then to check utility function

gdalinfo --version
GDAL 3.5.0dev-4f4292740a, released 2022/03/08
~/builds/proj$ proj
Rel. 8.2.1, January 1st, 2022
usage: proj [-bdeEfiIlmorsStTvVwW [args]] [+opt[=arg] ...] [file ...]

previous notes were here, I will update once I get this sorted: https://github.com/mdsumner/nectar/blob/master/gdalbuilder.md

mdsumner commented 2 years ago

working example with bbox, crs, and bands in 'vrt_connection' branch: https://github.com/mdsumner/gdal/tree/vrt_connection

autotest/ is in the gdal source tree

gdalinfo "vrt://autotest/gdrivers/data/netcdf/MODIS_ARRAY.nc?a_ullr=0,1,1,0&a_srs=EPSG:3857&a_ullr=100,200,1000,-300&bands=1,1"

mdsumner commented 2 years ago

now add '-ot' output type

 gdalinfo "vrt://autotest/gdrivers/data/netcdf/MODIS_ARRAY.nc?a_ullr=0,1,1,0&a_srs=EPSG:3031&a_ullr=100,200,1000,-300&bands=1,1&ot=Float64"

mdsumner commented 2 years ago

'-if' (doesn't seem to work)

'-expand' (fails sometimes ?? is there a transient temp file or something?)

gdalinfo "vrt://autotest/gcore/data/test_average_palette.tif?expand=rgba&if=NetCDF"

mdsumner commented 2 years ago

what is up with this? it doesn't work, and then it does ...

mdsumner commented 2 years ago

how to do GDAL executable

#include <iostream>
#include "gdal.h"
#include "ogr_spatialref.h"

bool this_way(char *input) {
  OGRSpatialReference srs;
  srs.SetFromUserInput(input);
  char *txt = nullptr;
  srs.exportToProj4(&txt);
  std::cout << txt << "\n";
  CPLFree(txt);
  return true;
}

bool cpl_way(CPLString input) {
  OGRSpatialReference srs;
  srs.SetFromUserInput(input);

  char *output = nullptr;
  srs.exportToProj4(&output);
  std::cout << output << "\n";
  CPLFree(output);
  return true;
}

bool that_way(char *input) {
  OGRSpatialReference *srs = nullptr;
  srs = new OGRSpatialReference;
  srs->SetFromUserInput(input);
  char *txt = nullptr;
  srs->exportToProj4(&txt);
  delete srs;
  std::cout << txt << "\n";

  CPLFree(txt);
  return true;
}

int main() {
  char input[] = "WGS84";
  bool yes = this_way(input);
  bool no  = that_way(input);
  CPLString   input2{};
  input2 = "WGS84";
  bool cpl = cpl_way(input2);
  return 1;
}

g++  -I/usr/include/gdal  -o program program.cpp -L/usr/lib -lgdal -lproj
./program

+proj=longlat +datum=WGS84 +no_defs +proj=longlat +datum=WGS84 +no_defs +proj=longlat +datum=WGS84 +no_defs

mdsumner commented 2 years ago

so, you can do spaces in the args, or escape them, committed just now

gdalinfo "vrt://autotest/gdrivers/data/netcdf/MODIS_ARRAY.nc?a_srs=EPSG:3857&bands=1,1&a_ullr=0\ 10\ 100\ -10" gdalinfo "vrt://autotest/gdrivers/data/netcdf/MODIS_ARRAY.nc?a_srs=EPSG:3857&bands=1,1&a_ullr=0 10 100 -10"

you can't use commas in the decimals, but gdalinfo normally can so we'd better use it's parsing (it can mix them even)

mdsumner commented 2 years ago

the spaces fail when it comes to the VRT text, you get '&' but not %20