The State of Arsenic in Nepal - 2003 - Harvard University ...

Table 6.3 presents arsenic tested tube wells by district with
location information and name of the data owner organization.
Geographic coordinates of some tube wells were found to be
inconsistent with their attribute location information, and
some were inconsistent with VDC and/or district boundaries.
Location information for about 12% of such tube wells was
not incorporated into the database due to those errors. Error
checking criteria of wells’ location information will be
discussed in following sub-chapter 6.4. However, 57% of
arsenic tested tube wells have location information in
geographic coordinates. Six districts (highlighted in Table
6.3) out of twenty in the table did not have location information.
6.1.2. District level data integration
The most common and useful well attributes from all acquired
data sets were used to present the state of arsenic in Nepal. A
standard format in Excel was developed based on these
identified attributes. Each individual data set acquired from
different organizations was converted and integrated into a
newly developed format. The goal of this data reorganization
was to create integrated data sets of arsenic tested wells in
uniform and standard format at the district level, so that state
of arsenic in district as well as national level could be presented
in different meaningful aspects. It is important to mention
here that organizations such as NRCS and RWSSSP had
additional useful health attributes in their data sets. But these
attributes were not present in other organization’s data set,
so they were not incorporated in the integrated data set.
Attributes which were incorporated in integrated data sets in
district level are listed in second column of Table 6.4.
Every data set provided by individual organization has an
identifier to identify wells in a data set. But that identifier may
not work efficiently when data sets from different sources are
integrated to create a single data set for a district. Mismatches
of data may occur. A new label, or identifier, to identify a tube
well in an integrated data set of arsenic tested wells was
created. The coding system for this identifier is illustrated
in Figure 6.3 The first two digits of the identifier
represents a district, the second three digits represents the
VDC of the corresponding district where the tube well is
located, and the last seven digits represents serial number of
the well in that VDC. The well ID 72-019-0000006 in the figure
represents the sixth tube well of Suda VDC of Kanchanpur
district in the integrated data set of arsenic tested tube wells.
Every well in the integrated data set also has its original
identifier (original well ID) given by data owner organization,
so that one can still process data based on the original
identifier. Data owner organizations may prefer to use their
original identifier to process their individual data set.
Kanchanpur
Coding System forWell ID
Figure 6.3.
6.1.3. Database design and creation of national database
Data consistency and integrity are crucial issues in an
integrated database. A standard database system was
designed and developed in Microsoft Access on the basis of
attributes identified in creating district level data sets. The
Table 6.4 presents the field names used for attributes of the
database and their descriptions.
Suda
72 - 019 - 0000006
Well ID
Well Serial
Number
Integrated data sets created through district level data
integration were converted into a newly developed system in
order to create an integrated national database of arsenic
tested tube wells in Nepal. This database comprises of
information of 18,635 wells of twenty districts collected up to
about the middle of 2003. About 10,618 wells in the database
have tube wells location information in geographic
coordinates. Tables 6.1, 6.2 and 6.3 give details about the
composition of data in the database by district, test method
used and source organization. A user-friendly interface of
the system helps users to browse and generate data sets of
tube wells with respect to arsenic concentration, data source
organization, test type and location in geographic
coordinates. Data sets can be generated in different levels
from VDC to country in different digital formats. Some of the
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