Import Title
Hello Ireland, I am proposing to import the Shannon/Erne navigation dataset, sourced from IWAI (Inland Waterways of Ireland) CSIG (Charts Special Interest Group).
Documentation
This is the source dataset’s website:
https://chartssig.iwai.ie/
This is the initial file I have prepared which shows the data after it was translated to OSM schema:
This is the modified OSM file:
The is a preview of the data, statically rendered:
https://tiles-openseamap-course-calculator.web.app/
License
I have checked that this data is compatible with the ODbL.
I have received permission Brian Willson to use this data to update OpenStreetMap via email conversation.
Abstract
Source data
The data has been collected by IWAI CSIG members and is made available to current IWAI members in various formats for use with naviagation systems.
It has been provided as a set of CSV file, using OSI grid references, along with a LABEL field containing the name or reference number as seen on the physical navigation mark. Navigation marks are grouped by type in each file, eg. Major Red, Minor Red, Major Green, etc.
The dataset contains ~1840 nodes
Data conversion
Multiple steps are needed to import the data:
- Concatenate the CSV files, and add the type of navigation mark to each row
- Import the combined CSV as a layer into QGIS
- Export the layer as GeoJSON using the EPSG:4326 projection
- Use a NodeJS script to enumerate each of the POINT features and generate an OSM file, adding the relevant seamark:* tags
Resources:
Preparation
From JOSM, install
- Map Paint Style
- JOSM Tagging Presets
- JOSM Tagging Validator
Data import
- Download an extract of all nodes containing a seamark:type attribute from OverPass
- Load both the OverPass extract and the generated IWAI OSM data into JOSM
- Starting from Limerick, moving North, compare the two layers visually and copy & paste IWAI nodes into the OverPass layer
- Where nodes appear to be duplicated, merge the two nodes and resolve any conflicts
a. The IWAI data is preferred over existing data, but the existing node is retained and updated
b. Cairns are combined with TopMarks where required
c. Use Bing aerial photos where possible to resolve conflicting mark locations - Validate the data
- Verify rendering of marks using jrender
Issues:
Possible: Rendering of Topmarks on Cairns Solved
Encountered: End of Naviation marks on the Shannon do not conform to either INT Section Q or CEVNI notice marks Worked around
** Encountered**: Lough Erne uses [fairly] unique navigation marks, which will cause some issues:
- They do not conform to IALA:
a. they are a red-white vertical pattern, with the white side indicating the side that should be passed, and red the “hazard” side
b. The topmark is a hemisphere, which is not available as a shape - They are directional, eg. from one direction the mark will be red-white, where as from the opposide direction the mark will be white-red. This makes it difficult to render on a chart in the usual manner. The The Erne Waterway Chart depicts them in a fashion that is not possible currently possible on OpenSeaMap*.
- I have some thoughts on how this could be done, however.
Final notes
I have tried to seek information from the OpenSeaMap project, but the project appears to have gone quite in recent years. If any community members know of contacts in said project, details would be much appreciated.
John Bayly