Updated QOD September 2021 (markdown)

QOD-September-2021.md

@@ -17,7 +17,8 @@ Virtual events will be taking place online (see links below) and in the links sh
 No | Name | Time | Speaker | Country | Language
 ---|------|------|-------------|---------|---------
 1 | Implementation of web-based groundwater information mapping projects with QGIS and Lizmap | [08h00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?year=2021&month=9&day=24&hour=08&min=00&sec=0&msg=QGISOpenDay-IMMO "click this link to find out the time in your local time zone") | Immo Blecher | South Africa | English
-2 | QGIS a vibrant Community| [21h30 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?year=2021&month=8&day=27&hour=21&min=30&sec=0&msg=QGISOpenDay-Touringmodelbuilder "click this link to find out the time in your local time zone") |  Luiz Motta | Brazil | Portuguese 
+2 | Automatic identification of ditches and streams in elevation data using raster algorithms | [13h00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?year=2021&month=9&day=24&hour=13&min=00&sec=0&msg=QGISOpenDay-Jacob "click this link to find out the time in your local time zone") | Jacob Levallius | Sweden | English
+3 | QGIS a vibrant Community| [21h30 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?year=2021&month=8&day=27&hour=21&min=30&sec=0&msg=QGISOpenDay-Touringmodelbuilder "click this link to find out the time in your local time zone") |  Luiz Motta | Brazil | Portuguese 
 
 **QGISOpenDay 25 September 2021**
 
@@ -46,7 +47,7 @@ No | Name | Role | Contact
 
 **Time:** 24 September 2021 [08h00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?year=2021&month=9&day=24&hour=08&min=00&sec=0&msg=QGISOpenDay-IMMO "click this link to find out the time in your local time zone").
 
-**Duration:** ~45min
+**Duration:** ~45 min
 
 **Venue:** [Youtube Live Stream Link]()
 
@@ -54,6 +55,18 @@ No | Name | Role | Contact
 
 **Description:** The web-based mapping of groundwater information is becoming a big trend all over the world. Many countries have excellent mapping websites, often with WMS links, some updated regularly, others stagnant. But in Southern Africa groundwater mapping websites are scarce and often outdated due to the fact that groundwater data is sitting in various databases that don't "talk to each other" and is difficult to get by. Recent drought situations have prompted various projects to bring groundwater information to the web, primarily to educate the public en encourage participation, but also to initiate sound groundwater management practices and policies by creating public-private partnerships. This presentation demonstrates some background and a few live examples of what can be done with QGIS and Lizmap to bring groundwater data to the web.
 
+## Automatic identification of ditches and streams in elevation data using raster algorithms
+
+**Time:** 24 September 2021 [13h00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?year=2021&month=9&day=24&hour=13&min=00&sec=0&msg=QGISOpenDay-IMMO "click this link to find out the time in your local time zone").
+
+**Duration:** ~40 min
+
+**Venue:** [Youtube Live Stream Link]()
+
+**Presenter:** Jacob Levallius
+
+**Description:** Hydrological flow models are today commonly made using surface elevation sourced from LIDAR data. One big problem with this elevation data when calculating water flow is that culverts aren't represented and therefore the elevation data needs to be modified. Culverts have to be identified, digitised and "burned" into the elevation raster. Culverts are usually found along ditches and streams and these can to some degree be identified visually in the elevation raster using hillside symbology. However, if ditches and streams could be automatically identified the process of finding culverts would be easier. This presentation shows how to automatically identify ditches and streams of certain sizes and shapes using raster calculations with slope, aspect and neighbourhood analysis. The resulting raster features are then converted to polylines for further workflows to find and digitise culverts.
+
 ## QGIS a vibrant Community
 
 **Time:**  24 September 2021 [21h30 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?year=2021&month=8&day=27&hour=21&min=30&sec=0&msg=QGISOpenDay-Touringmodelbuilder "click this link to find out the time in your local time zone").