diff --git a/Makefile b/Makefile
index 9b767d6..0df6ee9 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
 cesium_version:=$(shell cat $(CURDIR)/docker/cesium-version.txt)
+checkout:=$(shell cat $(CURDIR)/docker/cts-checkout.txt)
 GOFILES:=$(shell find . -name '*.go')
 
 install: $(GOFILES) assets/assets.go
@@ -13,13 +14,13 @@ assets/assets.go: .go-bindata data
 data/smallterrain-blank.terrain:
 	curl --location --progress-bar https://raw.github.com/geo-data/cesium-terrain-builder/master/data/smallterrain-blank.terrain > data/smallterrain-blank.terrain
 
-docker-local: docker/local/cesium-terrain-server.tar.gz docker/local/Cesium-$(cesium_version).zip
+docker-local: docker/local/cesium-terrain-server-$(checkout).tar.gz docker/local/Cesium-$(cesium_version).zip
 	docker build -t geodata/cesium-terrain-server:local docker
 
 docker/local/Cesium-$(cesium_version).zip: docker/cesium-version.txt
 	curl --location --progress-bar https://cesiumjs.org/releases/Cesium-$(cesium_version).zip > docker/local/Cesium-$(cesium_version).zip
 
-docker/local/cesium-terrain-server.tar.gz: $(GOFILES) docker/cesium-version.txt Makefile
-	tar --exclude data/* -czvf docker/local/cesium-terrain-server.tar.gz $(GOFILES) docker/cesium-version.txt Makefile data
+docker/local/cesium-terrain-server-$(checkout).tar.gz: $(GOFILES) docker/cts-checkout.txt docker/cesium-version.txt Makefile
+	git archive HEAD --prefix=cesium-terrain-server-$(checkout)/ --format=tar.gz -o docker/local/cesium-terrain-server-$(checkout).tar.gz
 
 .PHONY: docker-local install
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 6c3c4e8..ed21860 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -34,7 +34,7 @@ ENV GOPATH=/usr/local/go/_vendor:/usr/local/go GOBIN=/usr/local/bin
 
 # Install the terrain server
 ADD local/ /tmp/local/
-ADD install-terrain-server.sh /tmp/
+ADD cts-checkout.txt install-terrain-server.sh /tmp/
 RUN /tmp/install-terrain-server.sh
 
 # Install Cesium.js
diff --git a/docker/cts-checkout.txt b/docker/cts-checkout.txt
new file mode 100644
index 0000000..1f7391f
--- /dev/null
+++ b/docker/cts-checkout.txt
@@ -0,0 +1 @@
+master
diff --git a/docker/install-terrain-server.sh b/docker/install-terrain-server.sh
index ab2979d..377fc45 100755
--- a/docker/install-terrain-server.sh
+++ b/docker/install-terrain-server.sh
@@ -4,17 +4,20 @@
 # Install the terrain server
 #
 
-CTS_DIR=/usr/local/go/src/github.com/geo-data/cesium-terrain-server
+# If a local source code archive does not exist, get it from GitHub.
+checkout=`cat /tmp/cts-checkout.txt`
+archive="/tmp/local/cesium-terrain-server-${checkout}.tar.gz"
+if [ ! -f $archive ]; then
+    wget --no-verbose -O $archive "https://github.com/geo-data/cesium-terrain-server/archive/${checkout}.tar.gz" || exit 1
+fi
 
-# Extract the terrain server code
+# Set up the source directory
+CTS_DIR=/usr/local/go/src/github.com/geo-data/cesium-terrain-server
 mkdir -p $CTS_DIR || exit 1
 cd $CTS_DIR || exit 1
 
-if [ ! -f /tmp/local/cesium-terrain-server.tar.gz ]; then
-    git clone https://github.com/geo-data/cesium-terrain-server.git . || exit 1
-else
-    tar -xzvf /tmp/local/cesium-terrain-server.tar.gz || exit 1
-fi
+# Extract the terrain server code
+tar --strip-components=1 -xzf $archive || exit 1
 
 # Build and install the server
 make install || exit 1