open ( "docs/data/test_uk.shp", "r" ) as source : # Copy the source schema and add two new properties. append ( ys ) return sum ( xs * ( ys - ys ) for i in range ( 1, len ( coords ))) / 2.0 with fiona. """ xs, ys = map ( list, zip ( * coords )) xs. A value >= 0 indicates a counter-clockwise oriented ring. INFO ) def signed_area ( coords ): """Return the signed area enclosed by a ring using the linear time algorithm at. Import datetime import logging import sys import fiona logging. To track references to C objects to avoid crashes, and you can work with vectorĭata using familiar Python mapping accessors. TheĬopying is a constraint, but it simplifies programs. Python bindings if you want all fields and coordinates of a record. Ogr2ogr program – but Fiona’s performance is much better than OGR’s You just want to reproject or filter data files, nothing beats the More slow if you only need access to a single record field – and of course if These are simplerĪnd safer to use, but more memory intensive. Where OGR’s Python bindings (for example) use C pointers, FionaĬopies vector data from the data source to Python objects. Fiona trades memory and speed for simplicity and Please understand this: Fiona is designed to excel in a certain range of tasksĪnd is less optimal in others. Why? To eliminate unnecessary complication. Systems, no remote method calls all these concerns are left to other Python There are no layers, noĬursors, no geometric operations, no transformations between coordinate Kind of mappings as records back to files. It reads data records from files as GeoJSON-like mappings and writes the same Wrapper for vector data access functions from the OGR library. Fiona is concerned exclusively with the latter. The kinds of data in GIS are roughly divided into rasters representingĬontinuous scalar fields (land surface temperature or elevation, for example)Īnd vectors representing discrete entities like roads and administrativeīoundaries. Like nations and cities, but it’s become ubiquitous today thanks to accurateĪnd inexpensive global positioning systems, commoditization of satellite A generation ago, GIS was something done only by major institutions Understand changes in our physical, political, economic, and cultural Geographic information systems (GIS) help us plan, react to, and
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