From fb6ed7d9741e7226c70d45951863ad4c0c20d5df Mon Sep 17 00:00:00 2001
From: Brad Aagaard <baagaard@usgs.gov>
Date: Wed, 30 Sep 2026 21:15:50 -0600
Subject: [PATCH] FIX: Improve error message when reading values from time
 history database fails.

---
 CHANGES.md                                    |  5 +++++
 libsrc/spatialdata/spatialdb/TimeHistoryIO.cc | 12 ++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 2c67149..c84e5f9 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,8 @@
+## main
+
+* **Fixed**
+  * Improved error message when reading values from time history database fails.
+
 ## Version 4.0.1 (2026/08/17)
 
 * **Added**
diff --git a/libsrc/spatialdata/spatialdb/TimeHistoryIO.cc b/libsrc/spatialdata/spatialdb/TimeHistoryIO.cc
index b2b2301..75d3d58 100644
--- a/libsrc/spatialdata/spatialdb/TimeHistoryIO.cc
+++ b/libsrc/spatialdata/spatialdb/TimeHistoryIO.cc
@@ -125,7 +125,8 @@ spatialdata::spatialdb::TimeHistoryIO::read(double** ptime,
         double* time = (size > 0) ? new double[size] : 0;
         double* amplitude = (size > 0) ? new double[size] : 0;
 
-        for (size_t i = 0; i < size; ++i) {
+        int count = 0;
+        for (size_t i = 0; i < size; ++i, ++count) {
             buffer.str(parser.next());
             buffer.clear();
             buffer >> time[i];
@@ -140,7 +141,14 @@ spatialdata::spatialdb::TimeHistoryIO::read(double** ptime,
         } // for
 
         if (!filein.good()) {
-            throw std::runtime_error("Unknown error while reading.");
+            std::ostringstream msg;
+            if (count < size) {
+                msg << "Read " << count << " out of " << size << " points before encountering the I/O error.";
+            } else {
+                msg << "Error occurred while reading data for final point.\n"
+                    << "Make sure that the last line with data ends with an end-of-line character.";
+            } // if/else
+            throw std::runtime_error(msg.str());
         } // if
 
         delete[] *ptime;*ptime = time;