dparrini / Geodabase.jl

A .gdb geodatabase Julia interface

Geodatabase.jl

Implements an interface to the ESRI .gdb geodatabase files.

Installation

Copy the module to a desired location and use it with the code below:

include("Geodatabase.jl")
using .Geodatabase

Key Functions

Geodatabase.Database

Geodatabase.Database(file_path::String) => Geodatabase.Database

Creates a database connection to the path specified in file_path.

Geodatabase.Table

Geodatabase.Table(db::Database, table_name::String) => Geodatabase.Table

Opens a table file_name from db Database for queries.

Geodatabase.Search

Geodatabase.Search(table::Table, fields::AbstractString, where_clause::AbstractString) => Geodatabase.Query Geodatabase.Search(db::Database, table::AbstractString, fields::AbstractString, where_clause::AbstractString) => Geodatabase.Query

Returns a query for fields of the table meeting the where_clause criteria.

• fields = "*" to query all table columns.
• fields = "name1, name2, ..., name_n" to query a specific list of columns, in this specific order.
• where_clause = "" to query all rows.
• use common SQL statement operators to specify filters such as =, >, AND, OR, etc.

The returned value can be consumed only once (forward direction), for instance to produce a DataFrame or to write a CSV file. To reuse it, a reset! call must be made over the Search returned value.

Geodatabase.describe

Geodatabase.describe(obj) => nothing

Prints schema information (columns and types) of obj, which can be of the types Database, Table, Query, and Row.

Geodatabase.close

Geodatabase.close(obj) => nothing

Frees Geodatabase resources associated with the obj. It is called automatically when an Geodatabase.jl object (such as Database, Table, etc) is not used anymore.

Geodatabase.tablenames

Geodatabase.tablenames(db::Database) => Vector{AbstractString}

Returns a String list of the table names of db.

Geodatabase.columnnames

Geodatabase.columnnames(obj) => Vector{AbstractString}

Returns a String list of the column names of obj, which can be of the types Table, Query, and Row.

Geodatabase.reset!

Geodatabase.reset!(obj::GdbSearch) => Geodatabase.Query

Restores the results of a Geodatabase.Search call.

Examples

include("Geodatabase.jl")
using .Geodatabase

# Load a .gdb database
db = Geodatabase.Database("the_database.gdb")

# List available tables
println(Geodatabase.tablenames(db))

table = Geodatabase.Table(db, "\\a_table")

# Query all available data from a table
CSV.write("file.csv", Geodatabase.Search(table, "*", ""))

# Query some of the fields of a table and filter by one of the fields
DataFrames.DataFrame(Geodatabase.Search(table, "ObjectID, name, quantity", "quantity > 100"))

Printing available table schema

db = Geodatabase.Database("a_database.gdb")
table_names = Geodatabase.tablenames(db)

for table_name in table_names
  table = Geodatabase.Table(db, table_name)
  Geodatabase.describe(table)
end

Using the same query twice with reset!

query = Geodatabase.Search(table, "*", "")
CSV.write("file.csv", query)

Geodatabase.reset!(query)
println(DataFrames.DataFrame(query))