對應從事遙感與地理信息的同仁來說，gdal應該是所有工具中使用頻度最高的庫了，那麽在docker中使用gdal時，面臨的第一步就是構建gdal基礎鏡像，社區中引用最多的就是geodata提供的gdal基礎鏡像包，封裝的gdal最新版本是2.3.0dev。

geodata/gdal的docker在github上的地址如下：

https://github.com/geo-data/gdal-docker

根據該庫的提交記錄，其生成gdal鏡像的方法經歷了多次更新：

1 最初按照gdal官網步驟自行編譯；

2 基於makefile采用make系統編譯；

3 基於gdal的travel ci 腳本進行編譯。

dockerfile內容如下：

##
# geodata/gdal
#
# This creates an Ubuntu derived base image that installs the latest GDAL
# subversion checkout compiled with a broad range of drivers.  The build process
# is based on that defined in
# <https://github.com/OSGeo/gdal/blob/trunk/.travis.yml>
#

# Ubuntu 14.04 Trusty Tahyr
FROM ubuntu:trusty

MAINTAINER Homme Zwaagstra 
 
<hrz@geodata.soton.ac.uk>

# Install the application.
ADD . /usr/local/src/gdal-docker/
RUN /usr/local/src/gdal-docker/build.sh

# Externally accessible data is by default put in /data
WORKDIR /data
VOLUME ["/data"]

# Output version and capabilities by default.
CMD gdalinfo --version && gdalinfo --formats && ogrinfo --formats
 

基於ubuntu:trusty基礎鏡像，復制鏡像構建相關內容到鏡像的/usr/local/src/gdal-docker目錄，利用build.sh腳本執行構建操作。

build.sh內容如下：

#!/bin/sh

##
# Install GDAL from within a docker container
#
# This script is designed to be run from within a docker container in order to
# install GDAL. It delegates to `before_install.sh` and `install.sh` which are
# patched from the Travis CI configuration in the GDAL repository.
#

set -e

DIR=$(dirname "$(readlink -f "$0")")
GDAL_VERSION=$(cat ${DIR}/gdal-checkout.txt)

export DEBIAN_FRONTEND=noninteractive

# Set the locale. Required for subversion to work on the repository.
update-locale LANG="C.UTF-8"
dpkg-reconfigure locales
. /etc/default/locale
export LANG

# Instell prerequisites.
apt-get update -y
apt-get install -y         software-properties-common         wget         unzip         subversion         ccache         clang-3.5         patch         python-dev         ant

# Everything happens under here.
cd /tmp

# Get GDAL.
svn checkout --quiet "http://svn.osgeo.org/gdal/${GDAL_VERSION}/" /tmp/gdal/

# Install GDAL.
cd /tmp/gdal

# Apply our build patches.
patch ./gdal/ci/travis/trusty_clang/before_install.sh ${DIR}/before_install.sh.patch
patch ./gdal/ci/travis/trusty_clang/install.sh ${DIR}/install.sh.patch

# Do the build.
. ./gdal/ci/travis/trusty_clang/before_install.sh
. ./gdal/ci/travis/trusty_clang/install.sh

# Clean up.
apt-get autoremove -y
apt-get clean
rm -rf /var/lib/apt/lists/partial/* /tmp/* /var/tmp/*

設置GDAL_VERSION（從gdal-checkout.txt讀取，為trunk，表示從svn主幹分支下載源代碼），下載gdal源代碼到/tmp/gdal目錄，下載編譯器clang和python環境，對gdal的trusty_clang的travis安裝腳本打補丁（通過修改後調用diff工具生成patch）,安裝gdal，清理臨時文件。

docker社區的geodata/gdal鏡像dockerfile分析