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QGIS Planet

MovingPandas 0.19 released!

This release is the first to support GeoPandas 1.0.

Additionally, this release adds multiple new features, including:

For the full change log, check out the release page.

We have also revamped the documentation at https://movingpandas.readthedocs.io/ using the PyData Sphinx Theme:

On a related note: if you know what I need to change to get all Trajectory functions listed in the TOC on the right, please let me know.

New MovingPandas tutorial: taking OGC Moving Features full circle with MF-JSON

Last week, I had the pleasure to meet some of the people behind the OGC Moving Features Standard Working group at the IEEE Mobile Data Management Conference (MDM2024). While chatting about the Moving Features (MF) support in MovingPandas, I realized that, after the MF-JSON update & tutorial with official sample post, we never published a complete tutorial on working with MF-JSON encoded data in MovingPandas.

The current MovingPandas development version (to be release as version 0.19) supports:

  • Reading MF-JSON MovingPoint (single trajectory features and trajectory collections)
  • Reading MF-JSON Trajectory
  • Writing MovingPandas Trajectories and TrajectoryCollections to MF-JSON MovingPoint

This means that we can now go full circle: reading — writing — reading.

Reading MF-JSON

Both MF-JSON MovingPoint encoding and Trajectory encoding can be read using the MovingPandas function read_mf_json(). The complete Jupyter notebook for this tutorial is available in the project repo.

Here we read one of the official MF-JSON MovingPoint sample files:

traj = mpd.read_mf_json('data/movingfeatures.json')

Writing MF-JSON

To write MF-JSON, the Trajectory and TrajectoryCollection classes provide a to_mf_json() function:

The resulting Python dictionary in MF-JSON MovingPoint encoding can then be saved to a JSON file, and then read again:

import json
with open('mf1.json', 'w') as json_file:
    json.dump(mf_json, json_file, indent=4)

Similarly, we can read any arbitrary trajectory data set and save it to MF-JSON.

For example, here we use our usual Geolife sample:

gdf = gp.read_file('data/demodata_geolife.gpkg')
tc = mpd.TrajectoryCollection(gdf, 'trajectory_id', t='t')
mf_json = tc.to_mf_json(temporal_columns=['sequence'])

And reading again

import json
with open('mf5.json', 'w') as json_file:
    json.dump(mf_json, json_file, indent=4)
tc = mpd.read_mf_json('mf5.json', traj_id_property='trajectory_id' )

Conclusion

The implemented MF-JSON support covers the basic usage of the encodings. There are some fine details in the standard, such as the distinction of time-varying attribute with linear versus step-wise interpolation, which MovingPandas currently does not support.

If you are working with movement data, I would appreciate if you can give the improved MF-JSON support a spin and report back with your experiences.

New interactive trajectory plots for MovingPandas & experiments on their interpretation using ChatGPT 4o

With the release of GeoPandas 1.0 this month, we’ve been finally able to close a long-standing issue in MovingPandas by adding support for the explore function which provides interactive maps using Folium and Leaflet.

Explore() will be available in the upcoming MovingPandas 0.19 release if your Python environment includes GeoPandas >= 1.0 and Folium. Of course, if you are curious, you can already test this new functionality using the current development version.

This enables users to access interactive trajectory plots even in environments where it is not possible to install geoviews / hvplot (the previously only option for interactive plots in MovingPandas).

I really like the legend for the speed color gradient, but unfortunately, the legend labels are not readable on the dark background map since they lack the semi-transparent white background that has been applied to the scale bar and credits label.

Speaking of reading / interpreting the plots …

You’ve probably seen the claims that AI will help make tools more accessible. Clearly AI can interpret and describe photos, but can it also interpret MovingPandas plots?

ChatGPT 4o interpretations of MovingPandas plots

Not bad.

And what happens if we ask it to interpret the animated GIF from the beginning of the blog post?

So it looks like ChatGPT extracts 12 frames and analyzes them to answer our question:

Its guesses are not completely off but it made up the facts such as that the view shows “how traffic speeds vary over time”.

The problem remains that models such as ChatGPT rather make up interpretations than concede when they do not have enough information to make a reliable statement.

New Trajectools 2.1 and MovingPandas 0.18 releases

Today marks the 2.1 release of Trajectools for QGIS. This release adds multiple new algorithms and improvements. Since some improvements involve upstream MovingPandas functionality, I recommend to also update MovingPandas while you’re at it.

If you have installed QGIS and MovingPandas via conda / mamba, you can simply:

conda activate qgis
mamba install movingpandas=0.18

Afterwards, you can check that the library was correctly installed using:

import movingpandas as mpd
mpd.show_versions()

Trajectools 2.1

The new Trajectools algorithms are:

  • Trajectory overlay — Intersect trajectories with polygon layer
  • Privacy — Home work attack (requires scikit-mobility)
    • This algorithm determines how easy it is to identify an individual in a dataset. In a home and work attack the adversary knows the coordinates of the two locations most frequently visited by an individual.
  • GTFS — Extract segments (requires gtfs_functions)
  • GTFS — Extract shapes (requires gtfs_functions)

Furthermore, we have fixed issue with previously ignored minimum trajectory length settings.

Scikit-mobility and gtfs_functions are optional dependencies. You do not need to install them, if you do not want to use the corresponding algorithms. In any case, they can be installed using mamba and pip:

mamba install scikit-mobility
pip install gtfs_functions

MovingPandas 0.18

This release adds multiple new features, including

  • Method chaining support for add_speed(), add_direction(), and other functions
  • New TrajectoryCollection.get_trajectories(obj_id) function
  • New trajectory splitter based on heading angle
  • New TrajectoryCollection.intersection(feature) function
  • New plotting function hvplot_pts()
  • Faster TrajectoryCollection operations through multi-threading
  • Added moving object weights support to trajectory aggregator

For the full change log, check out the release page.

Getting started with pygeoapi processes

Today’s post is a quick introduction to pygeoapi, a Python server implementation of the OGC API suite of standards. OGC API provides many different standards but I’m particularly interested in OGC API – Processes which standardizes geospatial data processing functionality. pygeoapi implements this standard by providing a plugin architecture, thereby allowing developers to implement custom processing workflows in Python.

I’ll provide instructions for setting up and running pygeoapi on Windows using Powershell. The official docs show how to do this on Linux systems. The pygeoapi homepage prominently features instructions for installing the dev version. For first experiments, however, I’d recommend using a release version instead. So that’s what we’ll do here.

As a first step, lets install the latest release (0.16.1 at the time of writing) from conda-forge:

conda create -n pygeoapi python=3.10
conda activate pygeoapi
mamba install -c conda-forge pygeoapi

Next, we’ll clone the GitHub repo to get the example config and datasets:

cd C:\Users\anita\Documents\GitHub\
git clone https://github.com/geopython/pygeoapi.git
cd pygeoapi\

To finish the setup, we need some configurations:

cp pygeoapi-config.yml example-config.yml  
# There is a known issue in pygeoapi 0.16.1: https://github.com/geopython/pygeoapi/issues/1597
# To fix it, edit the example-config.yml: uncomment the TinyDB option in the server settings (lines 51-54)

$Env:PYGEOAPI_CONFIG = "F:/Documents/GitHub/pygeoapi/example-config.yml"
$Env:PYGEOAPI_OPENAPI = "F:/Documents/GitHub/pygeoapi/example-openapi.yml"
pygeoapi openapi generate $Env:PYGEOAPI_CONFIG --output-file $Env:PYGEOAPI_OPENAPI

Now we can start the server:

pygeoapi serve

And once the server is running, we can send requests, e.g. the list of processes:

curl.exe http://localhost:5000/processes

And, of course, execute the example “hello-world” process:

curl.exe --% -X POST http://localhost:5000/processes/hello-world/execution -H "Content-Type: application/json" -d "{\"inputs\":{\"name\": \"hi there\"}}"

As you can see, writing JSON content for curl is a pain. Luckily, pyopenapi comes with a nice web GUI, including Swagger UI for playing with all the functionality, including the hello-world process:

It’s not really a geospatial hello-world example, but it’s a first step.

Finally, I wan’t to leave you with a teaser since there are more interesting things going on in this space, including work on OGC API – Moving Features as shared by the pygeoapi team recently:

So, stay tuned.

Hi ‘Geocomputation with Python’

Today, I want to point out a blog post over at

https://geocompx.org/post/2023/geocompy-bp1/

In this post, Jakub Nowosad introduces our book “Geocomputation with Python”, also known as geocompy. It is an open-source book on geographic data analysis with Python, written by Michael Dorman, Jakub Nowosad, Robin Lovelace, and me with contributions from others. You can find it online at https://py.geocompx.org/

Mapping relationships between Neo4j spatial nodes with GeoPandas

Previously, we mapped neo4j spatial nodes. This time, we want to take it one step further and map relationships.

A prime example, are the relationships between GTFS StopTime and Trip nodes. For example, this is the Cypher query to get all StopTime nodes of Trip 17:

MATCH 
    (t:Trip  {id: "17"})
    <-[:BELONGS_TO]-
    (st:StopTime) 
RETURN st

To get the stop locations, we also need to get the stop nodes:

MATCH 
    (t:Trip {id: "17"})
    <-[:BELONGS_TO]-
    (st:StopTime)
    -[:STOPS_AT]->
    (s:Stop)
RETURN st ,s

Adapting our code from the previous post, we can plot the stops:

from shapely.geometry import Point

QUERY = """MATCH (
    t:Trip {id: "17"})
    <-[:BELONGS_TO]-
    (st:StopTime)
    -[:STOPS_AT]->
    (s:Stop)
RETURN st ,s
ORDER BY st.stopSequence
"""

with driver.session(database="neo4j") as session:
    tx = session.begin_transaction()
    results = tx.run(QUERY)
    df = results.to_df(expand=True)
    gdf = gpd.GeoDataFrame(
        df[['s().prop.name']], crs=4326,
        geometry=df["s().prop.location"].apply(Point)
    )

tx.close() 
m = gdf.explore()
m

Ordering by stop sequence is actually completely optional. Technically, we could use the sorted GeoDataFrame, and aggregate all the points into a linestring to plot the route. But I want to try something different: we’ll use the NEXT_STOP relationships to get a DataFrame of the start and end stops for each segment:

QUERY = """
MATCH (t:Trip {id: "17"})
   <-[:BELONGS_TO]-
   (st1:StopTime)
   -[:NEXT_STOP]->
   (st2:StopTime)
MATCH (st1)-[:STOPS_AT]->(s1:Stop)
MATCH (st2)-[:STOPS_AT]->(s2:Stop)
RETURN st1, st2, s1, s2
"""

from shapely.geometry import Point, LineString

def make_line(row):
    s1 = Point(row["s1().prop.location"])
    s2 = Point(row["s2().prop.location"])
    return LineString([s1,s2])

with driver.session(database="neo4j") as session:
    tx = session.begin_transaction()
    results = tx.run(QUERY)
    df = results.to_df(expand=True)
    gdf = gpd.GeoDataFrame(
        df[['s1().prop.name']], crs=4326,
        geometry=df.apply(make_line, axis=1)
    )

tx.close() 
gdf.explore(m=m)

Finally, we can also use Cypher to calculate the travel time between two stops:

MATCH (t:Trip {id: "17"})
   <-[:BELONGS_TO]-
   (st1:StopTime)
   -[:NEXT_STOP]->
   (st2:StopTime)
MATCH (st1)-[:STOPS_AT]->(s1:Stop)
MATCH (st2)-[:STOPS_AT]->(s2:Stop)
RETURN st1.departureTime AS time1, 
   st2.arrivalTime AS time2, 
   s1.location AS geom1, 
   s2.location AS geom2, 
   duration.inSeconds(
      time(st1.departureTime), 
      time(st2.arrivalTime)
   ).seconds AS traveltime

As always, here’s the notebook: https://github.com/anitagraser/QGIS-resources/blob/master/qgis3/notebooks/neo4j.ipynb

Adding basemaps to PyQGIS maps in Jupyter notebooks

In the previous post, we investigated how to bring QGIS maps into Jupyter notebooks.

Today, we’ll take the next step and add basemaps to our maps. This is trickier than I would have expected. In particular, I was fighting with “invalid” OSM tile layers until I realized that my QGIS application instance somehow lacked the “WMS” provider.

In addition, getting basemaps to work also means that we have to take care of layer and project CRSes and on-the-fly reprojections. So let’s get to work:

from IPython.display import Image
from PyQt5.QtGui import QColor
from PyQt5.QtWidgets import QApplication
from qgis.core import QgsApplication, QgsVectorLayer, QgsProject, QgsRasterLayer, \
    QgsCoordinateReferenceSystem, QgsProviderRegistry, QgsSimpleMarkerSymbolLayerBase
from qgis.gui import QgsMapCanvas
app = QApplication([])
qgs = QgsApplication([], False)
qgs.setPrefixPath(r"C:\temp", True)  # setting a prefix path should enable the WMS provider
qgs.initQgis()
canvas = QgsMapCanvas()
project = QgsProject.instance()
map_crs = QgsCoordinateReferenceSystem('EPSG:3857')
canvas.setDestinationCrs(map_crs)
print("providers: ", QgsProviderRegistry.instance().providerList())

To add an OSM basemap, we use the xyz tiles option of the WMS provider:

urlWithParams = 'type=xyz&url=https://tile.openstreetmap.org/{z}/{x}/{y}.png&zmax=19&zmin=0&crs=EPSG3857'
rlayer = QgsRasterLayer(urlWithParams, 'OpenStreetMap', 'wms')  
print(rlayer.crs())
if rlayer.isValid():
    project.addMapLayer(rlayer)
else:
    print('invalid layer')
    print(rlayer.error().summary()) 

If there are issues with the WMS provider, rlayer.error().summary() should point them out.

With both the vector layer and the basemap ready, we can finally plot the map:

canvas.setExtent(rlayer.extent())
plot_layers([vlayer,rlayer])

Of course, we can get more creative and style our vector layers:

vlayer.renderer().symbol().setColor(QColor("yellow"))
vlayer.renderer().symbol().symbolLayer(0).setShape(QgsSimpleMarkerSymbolLayerBase.Star)
vlayer.renderer().symbol().symbolLayer(0).setSize(10)
plot_layers([vlayer,rlayer])

And to switch to other basemaps, we just need to update the URL accordingly, for example, to load Carto tiles instead:

urlWithParams = 'type=xyz&url=http://basemaps.cartocdn.com/dark_all/{z}/{x}/{y}.png&zmax=19&zmin=0&crs=EPSG3857'
rlayer2 = QgsRasterLayer(urlWithParams, 'Carto', 'wms')  
print(rlayer2.crs())
if rlayer2.isValid():
    project.addMapLayer(rlayer2)
else:
    print('invalid layer')
    print(rlayer2.error().summary()) 
    
plot_layers([vlayer,rlayer2])

You can find the whole notebook at: https://github.com/anitagraser/QGIS-resources/blob/master/qgis3/notebooks/basemaps.ipynb

Data engineering for Mobility Data Science (with Python and DVC)

This summer, I had the honor to — once again — speak at the OpenGeoHub Summer School. This time, I wanted to challenge the students and myself by not just doing MovingPandas but by introducing both MovingPandas and DVC for Mobility Data Science.

I’ve previously written about DVC and how it may be used to track geoprocessing workflows with QGIS & DVC. In my summer school session, we go into details on how to use DVC to keep track of MovingPandas movement data analytics workflow.

Here is the recording of the session live stream and you can find the materials at https://github.com/movingpandas/movingpandas-examples/blob/opengeohub2023/README.md


This post is part of a series. Read more about movement data in GIS.

Comparing geographic data analysis in R and Python

Today, I want to point out a blog post over at

https://geocompx.org/post/2023/ogh23/

written together with my fellow “Geocomputation with Python” co-authors Robin Lovelace, Michael Dorman, and Jakub Nowosad.

In this blog post, we talk about our experience teaching R and Python for geocomputation. The context of this blog post is the OpenGeoHub Summer School 2023 which has courses on R, Python and Julia. The focus of the blog post is on geographic vector data, meaning points, lines, polygons (and their ‘multi’ variants) and the attributes associated with them. We plan to cover raster data in a future post.

How to use Kaggle’s Taxi Trajectory Data in MovingPandas

Kaggle’s “Taxi Trajectory Data from ECML/PKDD 15: Taxi Trip Time Prediction (II) Competition” is one of the most used mobility / vehicle trajectory datasets in computer science. However, in contrast to other similar datasets, Kaggle’s taxi trajectories are provided in a format that is not readily usable in MovingPandas since the spatiotemporal information is provided as:

  • TIMESTAMP: (integer) Unix Timestamp (in seconds). It identifies the trip’s start;
  • POLYLINE: (String): It contains a list of GPS coordinates (i.e. WGS84 format) mapped as a string. The beginning and the end of the string are identified with brackets (i.e. [ and ], respectively). Each pair of coordinates is also identified by the same brackets as [LONGITUDE, LATITUDE]. This list contains one pair of coordinates for each 15 seconds of trip. The last list item corresponds to the trip’s destination while the first one represents its start;

Therefore, we need to create a DataFrame with one point + timestamp per row before we can use MovingPandas to create Trajectories and analyze them.

But first things first. Let’s download the dataset:

import datetime
import pandas as pd
import geopandas as gpd
import movingpandas as mpd
import opendatasets as od
from os.path import exists
from shapely.geometry import Point

input_file_path = 'taxi-trajectory/train.csv'

def get_porto_taxi_from_kaggle():
    if not exists(input_file_path):
        od.download("https://www.kaggle.com/datasets/crailtap/taxi-trajectory")

get_porto_taxi_from_kaggle()
df = pd.read_csv(input_file_path, nrows=10, usecols=['TRIP_ID', 'TAXI_ID', 'TIMESTAMP', 'MISSING_DATA', 'POLYLINE'])
df.POLYLINE = df.POLYLINE.apply(eval)  # string to list
df

And now for the remodelling:

def unixtime_to_datetime(unix_time):
    return datetime.datetime.fromtimestamp(unix_time)

def compute_datetime(row):
    unix_time = row['TIMESTAMP']
    offset = row['running_number'] * datetime.timedelta(seconds=15)
    return unixtime_to_datetime(unix_time) + offset

def create_point(xy):
    try: 
        return Point(xy)
    except TypeError:  # when there are nan values in the input data
        return None
 
new_df = df.explode('POLYLINE')
new_df['geometry'] = new_df['POLYLINE'].apply(create_point)
new_df['running_number'] = new_df.groupby('TRIP_ID').cumcount()
new_df['datetime'] = new_df.apply(compute_datetime, axis=1)
new_df.drop(columns=['POLYLINE', 'TIMESTAMP', 'running_number'], inplace=True)
new_df

And that’s it. Now we can create the trajectories:

trajs = mpd.TrajectoryCollection(
    gpd.GeoDataFrame(new_df, crs=4326), 
    traj_id_col='TRIP_ID', obj_id_col='TAXI_ID', t='datetime')
trajs.hvplot(title='Kaggle Taxi Trajectory Data', tiles='CartoLight')

That’s it. Now our MovingPandas.TrajectoryCollection is ready for further analysis.

By the way, the plot above illustrates a new feature in the recent MovingPandas 0.16 release which, among other features, introduced plots with arrow markers that show the movement direction. Other new features include a completely new custom distance, speed, and acceleration unit support. This means that, for example, instead of always getting speed in meters per second, you can now specify your desired output units, including km/h, mph, or nm/h (knots).


This post is part of a series. Read more about movement data in GIS.

PyQGIS Jupyter notebooks on Windows using Conda

The QGIS conda packages have been around for a while. One of their use cases, for example, is to allow Linux users to easily install multiple versions of QGIS.

Similarly, we’ve seen posts on using PyQGIS in Jupyter notebooks. However, I find the setup with *.bat files rather tricky.

This post presents a way to set up a conda environment with QGIS that is ready to be used in Jupyter notebooks.

The first steps are to create a new environment and install QGIS. I use mamba for the installation step because it is faster than conda but you can use conda as well:

(base) PS C:\Users\anita> conda create -n qgis python=3.9
(base) PS C:\Users\anita> conda activate qgis
(qgis) PS C:\Users\anita> mamba install -c conda-forge qgis=3.28.2 
(qgis) PS C:\Users\anita> qgis

If we now try to import the qgis module in Python, we get an error:

(qgis) PS C:\Users\anita> python
Python 3.9.15 | packaged by conda-forge | (main, Nov 22 2022, 08:41:22) [MSC v.1929 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import qgis
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'qgis'

To fix this error, we need to get the paths from the Python console inside QGIS:

import sys
sys.path
['H:/miniconda3/envs/qgis/Library/./python', 'C:/Users/anita/AppData/Roaming/QGIS/QGIS3\\profiles\\default/python', ... ]

This list of paths can be configured as the defaults for our qgis environment using conda develop:

(qgis) PS C:\Users\anita> conda activate base
(base) PS C:\Users\anita> mamba install conda-build -c conda-forge
(base) PS C:\Users\anita> conda develop -n qgis [list of paths from qgis python console] 

With this setup, the import should now work without errors:

(base) PS C:\Users\anita> conda activate qgis
(qgis) PS C:\Users\anita> python
Python 3.9.15 | packaged by conda-forge | (main, Nov 22 2022, 08:41:22) [MSC v.1929 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import qgis

The example Jupyter notebook covers running a QGIS Processing algorithm and visualizing the results in the notebook using GeoPandas:

Head over to Github to find the full instructions: https://github.com/anitagraser/QGIS-resources/blob/master/qgis3/notebooks/hello-world.ipynb

MovingPandas v0.11 released!

The latest v0.11 release is now available from conda-forge.

This release contains some really cool new algorithms:

  • New minimum and Hausdorff distance measures #37
  • New functions to add a timedelta column and get the trajectory sampling interval #233 

As always, all tutorials are available from the movingpandas-examples repository and on MyBinder:

The new distance measures are covered in tutorial #11:

Computing distances between trajectories, as illustrated in tutorial #11

Computing distances between a trajectory and other geometry objects, as illustrated in tutorial #11

But don’t miss the great features covered by the other notebooks, such as outlier cleaning and smoothing:

Trajectory cleaning and smoothing, as illustrated in tutorial #10

If you have questions about using MovingPandas or just want to discuss new ideas, you’re welcome to join our discussion forum.

MovingPandas v0.10 released!

The latest v0.10 release is now available from conda-forge.

This release contains some really cool new algorithms:

If you have questions about using MovingPandas or just want to discuss new ideas, you’re welcome to join our recently opened discussion forum.

As always, all tutorials are available from the movingpandas-examples repository and on MyBinder:

Besides others examples, the movingpandas-examples repo contains the following tech demo: an interactive app built with Panel that demonstrates different MovingPandas stop detection parameters

To start the app, open the stopdetection-app.ipynb notebook and press the green Panel button in the Jupyter Lab toolbar:

Building an interactive app with geocoding in Jupyter Lab

This post aims to show you how to create quick interactive apps for prototyping and data exploration using Panel.

Specifically, the following example demos how to add geocoding functionality based on Geopy and Nominatim. As such, this example brings together tools we’ve previously touched on in Super-quick interactive data & parameter exploration and Geocoding with Geopy.

Here’s a quick preview of the resulting app in action:

To create this app, I defined a single function called my_plot which takes the address and desired buffer size as input parameters. Using Panel’s interact and servable methods, I’m then turning this function into the interactive app you’ve seen above:

import panel as pn
from geopy.geocoders import Nominatim
from utils.converting import location_to_gdf
from utils.plotting import hvplot_with_buffer

locator = Nominatim(user_agent="OGD.AT-Lab")

def my_plot(user_input="Giefinggasse 2, 1210 Wien", buffer_meters=1000):
    location = locator.geocode(user_input)
    geocoded_gdf = location_to_gdf(location, user_input)
    map_plot = hvplot_with_buffer(geocoded_gdf, buffer_meters, 
                                  title=f'Geocoded address with {buffer_meters}m buffer')
    return map_plot.opts(active_tools=['wheel_zoom']) 

kw = dict(user_input="Giefinggasse 2, 1210 Wien", buffer_meters=(0,10000))

pn.template.FastListTemplate(
    site="Panel", title="Geocoding Demo", 
    main=[pn.interact(my_plot, **kw)]
).servable();

You can find the full notebook in the OGD.AT Lab repository or run this notebook directly on MyBinder:

To open the Panel preview, press the green Panel button in the Jupyter Lab toolbar:

I really enjoy building spatial data exploration apps this way, because I can start off with a Jupyter notebook and – once I’m happy with the functionality – turn it into a pretty app that provides a user-friendly exterior and hides the underlying complexity that might scare away stakeholders.

Give it a try and share your own adventures. I’d love to see what you come up with.

Geospatial: where MovingPandas meets Leafmap

Many of you certainly have already heard of and/or even used Leafmap by Qiusheng Wu.

Leafmap is a Python package for interactive spatial analysis with minimal coding in Jupyter environments. It provides interactive maps based on folium and ipyleaflet, spatial analysis functions using WhiteboxTools and whiteboxgui, and additional GUI elements based on ipywidgets.

This way, Leafmap achieves a look and feel that is reminiscent of a desktop GIS:

Image source: https://github.com/giswqs/leafmap

Recently, Qiusheng has started an additional project: the geospatial meta package which brings together a variety of different Python packages for geospatial analysis. As such, the main goals of geospatial are to make it easier to discover and use the diverse packages that make up the spatial Python ecosystem.

Besides the usual suspects, such as GeoPandas and of course Leafmap, one of the packages included in geospatial is MovingPandas. Thanks, Qiusheng!

I’ve tested the mamba install today and am very happy with how this worked out. There is just one small hiccup currently, which is related to an upstream jinja2 issue. After installing geospatial, I therefore downgraded jinja:

mamba install -c conda-forge geospatial 
mamba install -c conda-forge jinja2=3.0

Of course, I had to try Leafmap and MovingPandas in action together. Therefore, I fired up one of the MovingPandas example notebook (here the example on clipping trajectories using polygons). As you can see, the integration is pretty smooth since Leafmap already support drawing GeoPandas GeoDataFrames and MovingPandas can convert trajectories to GeoDataFrames (both lines and points):

Clipped trajectory segments as linestrings in Leafmap
Leafmap includes an attribute table view that can be activated on user request to show, e.g. trajectory information
And, of course, we can also map the original trajectory points

Geospatial also includes the new dask-geopandas library which I’m very much looking forward to trying out next.

MovingPandas now supports local coordinates

MovingPandas 0.9rc3 has just been released, including important fixes for local coordinate support. Sports analytics is just one example of movement data analysis that uses local rather than geographic coordinates.

Many movement data sources – such as soccer players’ movements extracted from video footage – use local reference systems. This means that x and y represent positions within an arbitrary frame, such as a soccer field.

Since Geopandas and GeoViews support handling and plotting local coordinates just fine, there is nothing stopping us from applying all MovingPandas functionality to this data. For example, to visualize the movement speed of players:

Of course, we can also plot other trajectory attributes, such as the team affiliation.

But one particularly useful feature is the ability to use custom background images, for example, to show the soccer field layout:

To access the full example notebook, visit: https://github.com/anitagraser/movingpandas/blob/master/tutorials/5-local-coordinates.ipynb

An update to the MovingPandas examples repository will follow shortly.

MovingPandas v0.9 released!

The latest v0.9 release is now available from conda-forge.

This release contains some really cool new algorithms:

The Kalman filter in action on the Geolife sample: smoother, less jiggly trajectories.
Top-Down Time Ratio generalization aka trajectory compression in action: reduces the number of positions along the trajectory without altering the spatiotemporal properties, such as speed, too much.

These new algorithms were contributed by Lyudmil Vladimirov and George S. Theodoropoulos.

Behind the scenes, Ray Bell took care of moving testing from Travis to Github Actions, and together we worked through the steps to ensure that the source code is now properly linted using flake8 and black.

Being able to work with so many awesome contributors has made this release really special for me. It’s great to see the project attracting more developer interest.

As always, all tutorials are available from the movingpandas-examples repository and on MyBinder:

MovingPandas v0.8 released!

The latest v0.8 release is now available from conda-forge.

New features include:

  • More convenient creation of TrajectoryCollection objects from (Geo)DataFrames (#137)
  • Support for different geometry column names (#112)

Last week, I also had the pleasure to speak about MovingPandas at Carto’s Spatial Data Science Conference SDSC21:

As always, all tutorials are available from the movingpandas-examples repository and on MyBinder:

MovingPandas v0.7 released!

The latest v0.7 release is now available from conda-forge.

New features include:

As always, all tutorials are available from the movingpandas-examples repository and on MyBinder:

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