gnu: Add GPS Correlate.

* gnu/packages/gps.scm (gpscorrelate): New variable.

gnu/packages/gps.scm

@@ -19,11 +19,16 @@
 (define-module (gnu packages gps)
   #:use-module (guix packages)
   #:use-module (guix download)
+  #:use-module (guix git-download)
   #:use-module (guix build-system gnu)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (gnu packages which)
+  #:use-module (gnu packages pkg-config)
   #:use-module (gnu packages compression)
+  #:use-module (gnu packages docbook)
+  #:use-module (gnu packages geeqie)              ;exiv2
   #:use-module (gnu packages xml)
+  #:use-module (gnu packages gtk)
   #:use-module (gnu packages qt))
 
 (define-public gpsbabel
@@ -65,3 +70,59 @@ (define-public gpsbabel
 the back-end for other tools.  It does not convert, transfer, send, or
 manipulate maps.")
     (license license:gpl2+)))
+
+(define-public gpscorrelate
+  ;; This program is "lightly maintained", so to speak, so we end up taking it
+  ;; directly from its Git repo.
+  (let ((commit "365f6e1b3f"))
+    (package
+      (name "gpscorrelate")
+      (version (string-append "1.6.1." commit))
+      (source (origin
+                (method git-fetch)
+                (uri (git-reference
+                      (url "https://github.com/freefoote/gpscorrelate")
+                      (commit commit)))
+                (sha256
+                 (base32
+                  "006a6l8p38a4h7y2959sqrmjjn29d8pd50zj9nypcp5ph18nybjb"))))
+      (build-system gnu-build-system)
+      (arguments
+       `(#:phases (alist-replace
+                   'configure
+                   (lambda* (#:key inputs outputs #:allow-other-keys)
+                     ;; This is a rudimentary build system.
+                     (substitute* "Makefile"
+                       (("prefix[[:blank:]]*=.*$")
+                        (string-append "prefix = " (assoc-ref outputs "out")
+                                       "\n")))
+
+                     ;; Make sure the DocBook XML and XSL files are found.
+                     ;; Note: this is a space-separated list.
+                     (setenv "XML_CATALOG_FILES"
+                             (string-append (assoc-ref inputs "docbook-xml")
+                                            "/xml/dtd/docbook/catalog.xml "
+                                            (assoc-ref inputs "docbook-xsl")
+                                            "/xml/xsl/"
+                                            ,(package-full-name docbook-xsl)
+                                            "/catalog.xml")))
+                   %standard-phases)
+         #:tests? #f))
+      (inputs
+       `(("gtk+" ,gtk+-2)
+         ("libxml2" ,libxml2)
+         ("exiv2" ,exiv2)))
+      (native-inputs
+       `(("pkg-config" ,pkg-config)
+         ("docbook-xml" ,docbook-xml)
+         ("docbook-xsl" ,docbook-xsl)
+         ("libxslt" ,libxslt)))
+      (home-page "http://freefoote.dview.net/linux/gpscorrelate")
+      (synopsis "GPS photo correlation tool to geo-localize images")
+      (description
+       "GPS Correlate is a program to match a recorded GPS track with the EXIF
+tags in digital camera photos, and update the EXIF tags with the location that
+the photo was taken.  It does this by using the timestamp in the photo and
+finding a data point in the GPS track that matches, or interpolating a point
+between two other data points.")
+      (license license:gpl2+))))