Thank you for your videos.! I graduaded in GIS but it took me nearly 3 years to find a job. I forgot most stuff but thanks to your channel, I am able to keep up now. May God bless you!
Just in case this helps anyone with an invisible river in the future. I couldn't display the flow accumulation using classification, and couldn't see the points of high flow accumulation using stretch. This made it impossible to plot my outlet points. Then in the stretch symbology I changed the statistics from dataset to DRA, which basically made the river appear and makes it much easier to see at different zoom levels.
Thank you for such informative video. I am doing my research thesis on future water availability in a watershed which has river that bifurcates and rejoins again. Can you share video on how to create watershed in such case?
Thank you! Very informative video. Unfortunately, I can't change/edit the Id's on the attribute table. All of them are "0." Do you have any idea why and do you have any suggestions? Thanks again!
how do you know where to add pour points? and how many is needed? is there some kind of rule of thumb we should follow? increasing the points, changes the results right?
It just depends on where you want your catchment outlet to be. This actually ties back to your catchment delineation requirements. I'll give you an example. When constructing a bridge, we would need to know how much water would be passing through at that particular point of the river., and using a hydrological model, you could do all sorts of assessments related to the flow through that point where the bridge is going to be constructed. Having a delineated catchment that accounts for the drainage area corresponding to that point could be one of your requirements that you need to suffice before doing any hydrological modelling. For that, you will specify your pour point to be the point at which the bridge is going to be built, so that the delineated catchment will show you the corresponding drainage area. That'd just one instance of how one would decide to select where the pour point should be, and how of them there should be.
Thanks for your videos! Earlier on ESRI portal was information that for calculations and analysis, for registered users, a more detailed DEM (made by Airbus) is available. This data is not accessed directly, but through building geoprocessing models. Is it possible to check how Airbus data improves the results of the analysis?
I want to delineate watersheds in urban areas using GIS. Can I modify the terrain to capture local raises in terrain I.e. to obstruct the path of water?
Hi, its an SRTM digital elevation model, and you can download the elevation data for your area if interest as well for free. Check out this tutorial: th-cam.com/video/7LeGd6tuEr4/w-d-xo.html
This will depend on how much the natural runoff mechanisms are altered by the use of drains. This method can be applied to large areas, but in small localities and cities, the runoff should be studied based on the layout of the urban drainage system and all the components it entail.
Thank you for your videos.!
I graduaded in GIS but it took me nearly 3 years to find a job. I forgot most stuff but thanks to your channel, I am able to keep up now. May God bless you!
Keep making awesome videos like this. You are really one of the best teachers I have observed in Geo information.
Just in case this helps anyone with an invisible river in the future. I couldn't display the flow accumulation using classification, and couldn't see the points of high flow accumulation using stretch. This made it impossible to plot my outlet points. Then in the stretch symbology I changed the statistics from dataset to DRA, which basically made the river appear and makes it much easier to see at different zoom levels.
Your comment saved me. I was having exactly the same issue. Thank you so much!
Thank you for such informative video. I am doing my research thesis on future water availability in a watershed which has river that bifurcates and rejoins again. Can you share video on how to create watershed in such case?
Is there any reason why I cannot generate the D8 type of flow direction? All i see is black and white colour
Thank you! Very informative video. Unfortunately, I can't change/edit the Id's on the attribute table. All of them are "0." Do you have any idea why and do you have any suggestions? Thanks again!
how do you know where to add pour points? and how many is needed? is there some kind of rule of thumb we should follow? increasing the points, changes the results right?
It just depends on where you want your catchment outlet to be. This actually ties back to your catchment delineation requirements. I'll give you an example. When constructing a bridge, we would need to know how much water would be passing through at that particular point of the river., and using a hydrological model, you could do all sorts of assessments related to the flow through that point where the bridge is going to be constructed. Having a delineated catchment that accounts for the drainage area corresponding to that point could be one of your requirements that you need to suffice before doing any hydrological modelling. For that, you will specify your pour point to be the point at which the bridge is going to be built, so that the delineated catchment will show you the corresponding drainage area. That'd just one instance of how one would decide to select where the pour point should be, and how of them there should be.
@@geodeltalabs thank you for the detailed explanation. It all make sense now. Cheers!
Thanks for your videos!
Earlier on ESRI portal was information that for calculations and analysis, for registered users, a more detailed DEM (made by Airbus) is available. This data is not accessed directly, but through building geoprocessing models.
Is it possible to check how Airbus data improves the results of the analysis?
Thank you very much
You are welcome
I want to delineate watersheds in urban areas using GIS. Can I modify the terrain to capture local raises in terrain I.e. to obstruct the path of water?
very informative tutorial 👍
Thanks for sharing such information, may I know the source of that tif file ,where can I extract elevations for my study area ?
Hi, its an SRTM digital elevation model, and you can download the elevation data for your area if interest as well for free. Check out this tutorial: th-cam.com/video/7LeGd6tuEr4/w-d-xo.html
i ve a problem, the d8 results with 255 values not 8 values
Same problem here...
When I do the watershed tool it just makes a little line over my outlet point smh
Hi, if I know lat/long how I can find and download DEM file? Thanks in advance.
Also one doubt, can we use this same method to track the runoff of a small region or a city?
This will depend on how much the natural runoff mechanisms are altered by the use of drains. This method can be applied to large areas, but in small localities and cities, the runoff should be studied based on the layout of the urban drainage system and all the components it entail.
Hey, can you make the same tutorials in QGIS?
I don't have access to ArcGIS.
Hi, check this out th-cam.com/video/xwiHQlmEEjw/w-d-xo.html
@@geodeltalabs thank you!
I used fill tool but it gave me blank raster output
The key element you've overlooked in your efforts is the value of the drainage area. Without this, the entire exercise is rendered ineffective.
Just create a new column and calculate the area for each polygon. He explained the important parts of the process...
Brother. Thank you