To interact with the data from an EGF file outside of Owlet, the data can be exported to a different format. Upon visualize() being executed, the computer's default web browser will open and provide a preview of my_shape using the webpage geojson.ioīoth points from the EGF file are displayed on the map after running owlet.visualize(my_shape)ĮGF Files also support linestrings for mapping paths To visualize my_shape, call the visualize() function and pass my_shape to it. read_egf ( "folder/BostonParks.egf" ) Visualizing an EGF file For longer paths, it is neater to save the path to a variable. If the file path is short, it may be easier to pass the path directly in to the function like in the example below. in_file = "path/to/file/BostonParks.egf" my_shape = owlet.
owlet.read_egf()īelow, the EGF file is loaded and saved to a variable named my_shape. Since the read_egf() function is a part of the Owlet Python package, the function is called by typing owlet. Then pass the variable that hold the EGF file's path to the read_egf() function. To read an EGF file, begin by saving the path of the EGF file to a variable in your python script. When writing a new Python file, begin by importing Owlet. Once the EGF file is saved, create a new Python file and import Owlet.
To begin, save the EGF file example above to your computer as BostonParks.egf using a text editor such as Notepad.
To install owlet, type one of the following commands into the terminal or command line Windows > py - m pip install owlet MacOS / Linux > pip3 install owlet Using Owlet In an EGF file, each section / feature is separated by three blank lines and the file ends with a single blank line.Īn EGF file is a '.txt' file renamed to '.egf' A Feature Type Declaration (point, line, polygon)Įxample EFG file containing two placemarks: PT.EGF File Example OverviewĪn EGF file is comprised of three sections: An EGF file contains all of the necessary components required to define geospatial features- without overcomplicating it. Owlet is a Python library for interacting with and mapping EGF files.ĮGF, or Exact Geometry Format, is a file structure designed specifically for recording geo-data without traditional GIS software. Storing the data in this manner enables the data to be easily viewed by AutoCAD and read by the FME reader module.Įxtended entity data items may be used together to store more complex data, such as hyperlinks, where a display name string is grouped by control strings, related to a preceding location string.A Geospatial Python Package for Field Researchers Owlet and EGF: Developed for Field Researchers That is, the attribute data is stored with each attribute being a single extended entity string in the form =. When writing extended entity data, the FME features being output must structure their attributes in this way.
The interpreted format setting is described in Interpreted Format, for extended entity data. The AutoCAD writer is limited to creating 8K bytes per entity. The size of extended entity data that can be stored on a single entity is limited to 16K bytes. In the absence of data in the list format form, the writer will create extended entity data from attribute data in the interpreted format, when the DEFAULT_ATTR_STORAGE directive is set to extended_entity_data, or the autocad_attributes attribute is set to extended_entity_data. The AutoCAD writer understands both the list format and the interpreted format, creating extended entity data from attribute data in the list format form if they are present. The format that is actually used (if any) is dependent on the configuration of the remainder of the FME mapping file. It is important to remember that when extended entity data is read from an AutoCAD file, all three formats are stored within a single FME feature. The first two formats merely store the data as found in the drawing file in the feature, while the third format attempts to present the attribute information in a more useful manner. The AutoCAD reader attempts to make extended entity data as simple to use as possible by storing it in three different formats within the FME feature object. This data is typically used by applications to store attribute information. You are here: Popular Formats > Autodesk AutoCAD DWG/DXF Reader/Writer > Feature Representation > Extended Entity Data Extended Entity DataĮach entity in an AutoCAD file may have associated extended entity data.