groundwater vs time and rain data

You need to use GDW export, not overlay, as the data has a different keyset, best done via a script, for example:

**Operation
OUTPUT

**Command
EXPORT

**Properties
Type=Graph
Name=MON HYDROGRAPH A4L
Report_Variables=<ARRAY>
Title,Groundwater Level versus Time
Drawn,
Drawn Date,
Checked,
Checked Date,
Figure Number,
Scale Text,Not to Scale
</ARRAY>

**Spec
Project=datgel monitoring tool 3.00.gpj
Range=DMT-Piezo SP-7 Trans x 1|3|T1,DMT-Piezo SP-7 Trans x 1|4.5|SP1,DMT-Piezo SP-8 Trans x 2|4|T1,DMT-Piezo SP-8 Trans x 2|4.5|SP1,DMT-Piezo SP-8 Trans x 3|4|T1,DMT-Piezo SP-8 Trans x 3|4.5|SP1
ExportFile=pie graph.gdw
GraphIndependentDiv=12
GraphDependentDiv=10
SiteMapOnly=0
DbSourceMode=1
GDWPageName=A

Command Script
11/10/2015 12:16:53 AM 

**Operation
OUTPUT

**Command
EXPORT

**Properties
Type=Graph
Name=MON PRECIPITATION BARPLOT MULT A4L

**Spec
Project=datgel monitoring tool 3.00.gpj
Range=DMT-WS-2
ExportFile=pie graph.gdw
GraphIndependentDiv=12
GraphDependentMin=0
GraphDependentMax=40
GraphDependentDiv=10
SiteMapOnly=0
DbSourceMode=1
GDWPageName=A




**Operation
GDWOUTPUT


**Command
EXPORT

**Properties   

**Spec  
ExportFile=pie graph.pdf
IndividualDatasets=0
PDFBookmarkPath=ROOT,Graph - MON PRECIPITATION BARPLOT MULT A4L
PDFBookmarkRelation=1
Range=A
Resolution=600
GDWFile=pie graph.gdw

Note these lines

GDWPageName=A

ExportFile=pie graph.gdw

I have all this working in the Datgel Monitoring Tool gINT Add-In, after 2 years of trying I think buying something that works has some ROI.