Add implementation note on how missing values are handled

2 files changed, 11 insertions, 1 deletions

diff --git a/README.md b/README.md
index e69de29..ace1265 100644
--- a/README.md
+++ b/README.md
@@ -0,0 +1,10 @@
+# AnnotateChange
+
+## Implementation Notes
+
+* Missing values are skipped, so that gaps occur in the graph. X-values are 
+  however counted continuously, to ensure that this gap has nonzero width. 
+  Thus, when a change point is selected by an annotator after such a gap, its 
+  location can be found by retrieving the observation at the index *while 
+  including missing values*. This is in contrast to the approach where missing 
+  values are removed before the index is used to retrieve the data point.
diff --git a/app/static/js/makeChart.js b/app/static/js/makeChart.js
index 7004dc8..7049d8f 100644
--- a/app/static/js/makeChart.js
+++ b/app/static/js/makeChart.js
@@ -8,7 +8,7 @@ function preprocessData(data) {
 	for (i=0; i<data.values[0].raw.length; i++) {
 		d = data.values[0].raw[i];
 		if (isNaN(d)) {
-			n++;
+			n++; // keep counting!
 			if (run.length > 0)
 				cleanData.push(run);
 			run = [];