From 1ac74175557eb172ebd8ea1c9a8154ce562db27d Mon Sep 17 00:00:00 2001
From: snowman2 <alansnow21@gmail.com>
Date: Mon, 28 Feb 2022 10:47:19 -0600
Subject: [PATCH] BUG: Lazy load colormap through _manager.acquire() in merge

---
 docs/history.rst   |  1 +
 rioxarray/merge.py | 19 +++++++++++++------
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/docs/history.rst b/docs/history.rst
index 207e5685..1945ae80 100644
--- a/docs/history.rst
+++ b/docs/history.rst
@@ -3,6 +3,7 @@ History
 
 Latest
 -------
+- BUG: Lazy load colormap through _manager.acquire() in merge (issue #479)
 
 0.10.1
 -------
diff --git a/rioxarray/merge.py b/rioxarray/merge.py
index 45b88b75..928954d3 100644
--- a/rioxarray/merge.py
+++ b/rioxarray/merge.py
@@ -35,19 +35,26 @@ def __init__(self, xds: DataArray):
         try:
             rio_file = xds.rio._manager.acquire()
             self.profile = rio_file.profile
-            self.colormap = rio_file.colormap
         except AttributeError:
             self.profile = {}
-
-            def colormap(_):
-                return None
-
-            self.colormap = colormap
         self.profile.update(
             dtype=xds.dtype,
             crs=xds.rio.crs,
             nodata=xds.rio.nodata,
         )
+    
+    def colormap(self, *args, **kwargs):
+        """
+        Lazy load colormap through _manager.acquire()
+        for the scenario many file handles are opened
+
+        See: https://github.com/corteva/rioxarray/issues/479
+        """
+        try:
+            rio_file = self.xds.rio._manager.acquire()
+            return rio_file.colormap(*args, **kwargs)
+        except AttributeError:
+            return None
 
     def read(self, window, out_shape, *args, **kwargs) -> numpy.ma.array:
         # pylint: disable=unused-argument