Polygons To Points

This tool converts geoJSON or topoJSON polygon file to the "Nodes" CSV file with longitude and latitude coordinates of polygons centroids. Click "Submit" to download the file to your browser's download folder.

Flow Matrix to Flow List

This tool converts a CSV file containing a flow matrix into a flow list CSV file with columns for origin, destination, and volume. Select the orientation of the matrix and click "Submit" to download the flow CSV file to your browser's download folder.

Flow Matrix Orientation

Normalize Flows

Flow normalization helps remove the effect of total flow or population size by calculating modularity, i.e., the difference between the actual flow and the expected volume of flow for each pair of locations (nodes). We use the adjusted flow volume formula below to calculate the expected number of flows between locations.

For more details in modularity function please refer to Guo (2009).

1. Select your flow file with columns: origin, destination, and volume, then click "Submit".

2. Once processed, your file will be downloaded into your browser's download folder. It will have columns for origin, destination, modularity, rawvolume, and expectation. The modularity column reflects the difference between observed (rawvolume) and expected flow (expectation) using the given formula.

3. Modularity can be negative or positive. Negative values indicate fewer observed flows, while positive values suggest more observed flows than expected between origins and destinations.

Submit

Calculate Node Measures

Node measures calculated from flow data facilitate the creation of custom choropleth base map and node symbol map to provide context into the importance of nodes in the spatial network.

These measures currently include gross (total) flow, inflow, outflow, net flow, entropy, Gini coefficients, and degree measures. Koylu & Guo (2013).

1. Select your flow file with columns: origin, destination, and volume, then click "Submit".

2. Once processed, node measures file will be downloaded into your browser's download folder in a csv format that contains the nodeids that exist in the flow file and the basic node measures listed above.

3. You could join the node measure file to the choropleth or node symbol map to customize the symbology to reflect the selected measure.

Submit

Test Server Connection (beta)

This is a testing tool to connect to the backend Java code, which will provide more complicated analysis tools for pre-processing your data before visualization.

Only for testing use! please input your file below:

Testing result:

Video Tutorial

Tutorial Data

Example data sets are available to download and visualize with FlowMapper in the following link: https://github.com/geo-social/flowmapper.

Contact Email

Email: geo-social@uiowa.edu

Please contact us for any help using FlowMapper. Here are some example feedback:

Tell us about any bugs or problems you experienced with the interface and interactions.

Suggest new additions to FlowMapper. For example, if you would like us to enable any map projection that is not available, we are happy to include your suggested projection.

We are happy to hear any feedback and looking forward to improving your experience with FlowMapper.

Tutorial Data: github.com/geo-social/flowmapper

Website: www.geo-social.com

About FlowMapper

Version: 1.1.8

Developers: Geng Tian (2020-2022), Maeve Biscupski (2023 06-10)

Supervisor/Developer: Caglar Koylu

Citation: Please cite the reference below if you use FlowMapper in a manuscript or any form of publication:

Koylu, C., Tian, G., & Windsor, M. (2023). FlowMapper.org: A web-based framework for designing origin-destination flow maps, Journal of Maps, 19:1, DOI:10.1080/17445647.2021.1996479.

Error

Error.

Error: Nodes and flows do NOT match!

Please make sure the origin and destination IDs used in flow CSV file exist in the node file. Please upload your files and select the matching ID columns.