Final Project
Read from a csv file and write to a database table:
Prepare a Flood Insurance Rate Map (FIRM) database related to a
hydraulics study for Federal Emergency Management Agency (FEMA)
Flood Insurance Study (FIS)
Introduction to GIS Programming
Submitted By: Bibek Joshi
Email Address: bibek.joshi@gmail.com
05/16/2014
SUMMARY
This python script creates a personal geodatabase and adds a set of feature classes (point, polyline and
polygon) and a database table. Python dictionary is used to store the name and type of feature classes
and to store the name and type of fields. The script then reads from a comma-separated value (csv) file
and writes the data into the database table.
PURPOSE
FEMA publishes flood hazard map to support the National Flood Insurance Program (NFIP). The data are
summarized in Flood Insurance Study (FIS) and the maps are knows as Flood Insurance Rate Maps
(FIRMs). There are normally three major phases to a FEMA flood study of a stream: i) determine stream
discharges, ii) determine flood elevation and iii) map the floodplain. Phase i) and ii) are known as
hydrologic and hydraulic (H&H) study phase. After each phases of the study, the deliverables include
spatial files that have to follow certain guidelines. The guidelines for the GIS files submitted as a part of
the H&H study are outlined in the FIRM Database Technical Reference Document.
GEOPROCESSING TASKS
Following arcpy functions were used:
 AddError
 AddField_management
 AddMessage
 CreateFeatureclass_management
 CreateFeatureDataset_management
 CreateFileGBD_management
 CreateTable_management
 Delete_management
 Exists
 GetMessage
 InsertCursor
DIFFICULTIES/ ISSUES
The following difficulties were encountered:


The order in which the items in the Python dictionary are stored are different from the order in
which the items are printed. So, in order to print the items in the same order
collections.OrderedDict() function was used.
Initially the script could not write to a field type "DOUBLE" or any other non-string data type. In
the csv file the first row contains column header and the data were populated from the second
row. In the script, if-statement was used to add the rows starting from the second row.
However, when the values from the csv file are first read into each field, a field with double type
cannot store the header name which is a string. As a result, Python produced an error message
stating incompatible data type. This issue was resolved by 'consuming' the first row in the csv
file using next() function. Another option to resolve this issue is to use csv.DictReader function.

This is a unresolved issue: I could not find a function/process to convert a string into a variable
name. I have stored the name of the fields as a string in a dictionary. When a new row is created
and a value is assigned as in, irow.FIELDNAME = "", I was planning to use a loop to read from a
dictionary for the FIELDNAME. However, 'FIELDNAME' has to be a variable and not a string.
OUTCOME
In the fully developed form of this script, the script will automatically create a file geodatabase with
multiple feature classes that has a user-selected projection system. Each feature class and database
table will have multiple fields created based on a specific guideline. Then the script will automatically
read from a csv file and populate the database table.