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Questions tagged [flood]

A flood is an overflow of water that submerges land which is usually dry. Within GIS we often want to model a flood with terrain models.

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Water Depth, Velocity, Depth*Velocity Filtering using QGIS

I need to filter some hydraulic modelling results in QGIS as per the following specification: Exclude areas with a depth less than 10 mm AND depth x velocity (dV) below 0.125 m2/s; Exclude areas ...
Guest's user avatar
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Global Flood Database v1 unmask 'jrc_perm_water'

I am using Google Earth Engine to generate mean area flooded in electoral districts of India. What is a good way to remove the values of permanent water from the 'flooded' band and generate aggregate ...
Tarana Chauhan's user avatar
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1 answer
21 views

Supervised classification ALOS-PALSAR Google Earth Engine

I need to create a supervised classification for flood detection with ALOS PALSAR in Google Earth Engine. How can I do this?
Paula Torres's user avatar
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Flood: Layer error: Image.lt: If one image has no bands, the other must also have no bands. Got 0 and 1

I'm trying to copy the code of the video below but for my area Greece. It's about the Daniel flood. https://www.youtube.com/watch?v=hIoVwsAb_Pk&ab_channel=GeomaticsEngineering I write the code as ...
Evangelia Beli's user avatar
1 vote
1 answer
40 views

Runtime in ArcPy versus ArcGIS Pro

I have at least two hundred huge TIFF rasters that I'm trying to process into floodplain polygons. They are cursory flood depth rasters for pluvial, fluvial and coastal flooding. First, I need to set ...
Tebetheia's user avatar
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Get specific range of dates when flood value is low in GEE Sentinel-1

I am new at GEE and I am trying to do some flood analysis, I already have a time series of flood for one point, I did it getting the value from VV band of sentinel-1. Now I want to get the range of ...
Paula Torres's user avatar
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58 views

Sharing spatiotemporal data on web using QGIS

I have NetCDF data of predicting the flood and need to show them in web map. I read (and also tried), plugin QGIS2WEB is not friendly with temporal data and Temporal Controller plugin. Is there any ...
VikiM's user avatar
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QGIS 3D viewer autoupdate frames from temporal controller

I am using QGIS 3.30.3 and I am trying to make a cinematic with the 3D viewer of some flood tiles. I have a Digital elevation Model and a few flood tiles with temporal information. Using the temporal ...
luis castillo's user avatar
2 votes
1 answer
119 views

Using Otsu's Method to separate water and not-water in GEE

I am trying to separate permanent waterbody and not-water from Sentinel-1 image in earth engine. To do this I am taking a median and mean image for a month from a range of years and then using Otsu's ...
Raihan's user avatar
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2 votes
1 answer
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Representing polygon features using arrows that represent direction of orientation?

I have a polygon layer that stores results obtained from simulations run on a hydrological modelling software, ICM. A particular table within the attribute table of this polygon layer has details ...
Bernard Stokes's user avatar
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49 views

How to identify straight edges on raster

I have water surface elevation rasters that I would like to QC for "inorganic shapes" like the screenshot below that are a result of modeling errors. What would be the best method to ...
Tebetheia's user avatar
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Why is my code for flood pixel area calculation timing out?

I have made a flood map of Bangladesh following a tutorial. I am trying to determine the flood-affected land area by calculating pixel area. The map is displayed fine and the code for total area ...
Mosh's user avatar
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Cannot manage to clip DEM raster using vector for calculating flood depth on QGIS

I have a huge DEM that I want to clip on QGIS based on a flood vector layer so that I can easily calculate the flood depth based on the highest DEM value in the flooded area. I am trying to use the &...
qgisusser's user avatar
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22 views

Using values in raster to extend a raster/polygon to contour/LiDAR value

I'm using ArcMap. I have a raster of flood levels (LiDAR + a water depth). I want to add 50mm onto the flood level raster which I can do with raster calculator. But then what I want to do is 'extend' ...
Duck's user avatar
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How to combine vector data (census) with raster data (inundation)

I am hoping to find a way to create a map showing the overlap of flood inundation and social vulnerability in QGIS. I tried using zonal statistics, but it does not take into account the values, just ...
Ella's user avatar
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Creating time series flood inundation map using NetCDF future sea level and DEM

I want to design a GIS tool that visualizes flood inundation maps for future sea level rise. the data that I need to use are NetCDF of projected Sea level rise for 10-year slices and DEM. The idea is ...
Sahar's user avatar
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Urban watershed delineation for flash flood events

I am currently trying to create urban watersheds using the ending points of flash flood events (in the NOAA Storm Events Database) as outlet points for a city. While doing so, the watershed that is ...
Rohan Singh Wilkho's user avatar
1 vote
1 answer
116 views

Detect sharp changes in elevation

I've been scouring the forums to see if there is a way to detect sharp, unnatural elevation changes greater than a certain amount in ArcGIS Pro. I've run across an issue in some DEMs where there are ...
Tebetheia's user avatar
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Get output from this code

I get this error Error: Image. select: Pattern 'scale' did not match any bands. (Error code: 3) from this code. Map.centerObject(table); Map.addLayer(table); var before = ee.ImageCollection('...
sadaf's user avatar
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1 answer
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Issues implementing data fusion in EO Browser

I am trying to implement this custom script for flood mapping in EO Browser. I have added the datasets using the additional datasets button, and specified the required timelines, but I keep getting ...
Opegraphy's user avatar
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1 answer
119 views

Extracting information from flood zone shapefile

I have a individual land price data, and I am trying to get the flood hazard zone category using the flood hazard zone shape file (link here https://files.hawaii.gov/dbedt/op/gis/data/...
Metrics's user avatar
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1 answer
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Displaying water movement paths over grid in QGIS

I have an external .csv file with "From" cell, "To" cell, X, Y coordinates for the "From" cell, X Y coordinates for "To" cell and flow rate for water going from ...
user1889930's user avatar
2 votes
1 answer
168 views

Correspondence of 0m elevation height of a digital elevation model (Copernicus DEM) to mean sea level

I want to model future coastal flooding caused by sea-level rise under the latest IPCC scenarios at global scale. To this end, I use the Copernicus Digital Elevation Model (Copernicus DEM: https://...
Circus pygargus's user avatar
1 vote
2 answers
451 views

QGIS - How to split and display Population Data according to District/Province?

I'm a complete beginner in QGIS, currently self-teaching myself through Youtube. Current Problem: To split and display population data according to district/province Project Background: To measure ...
Senpai-C's user avatar
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1 answer
141 views

Creating a layer showing difference before/after flood (raster)

I ran a supervised classification on two satellite images - (i) before and (ii) after a flood. Now even before the floods, there were pre-existing water bodies which obviously don't count as flooded ...
Madhav Warawdekar's user avatar
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1 answer
56 views

Should I re-scale all the dataset to one scale before running them into model?

I have been working on the Flood susceptibility modelling and also have identified, collected and generated data of around 26 controlling factors(indicators). Furthermore, i'm going to put them into ...
Abhishek Gupta's user avatar
1 vote
0 answers
87 views

Generate topographical index from a digital surface model (DSM) to generate a flood susceptibility map [closed]

I'm performing a random forest model to generate a flood susceptibility map, I have LiDAR data from the study area where I generated Digital Surface Model (DSM) and Digital Terrain Model (DTM) raster ...
Makita's user avatar
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1 vote
1 answer
830 views

Layer error: Image.rename: The number of names (1) must match the number of bands (10)

I am using Landsat 7 data (ee.ImageCollection("LANDSAT/LE07/C01/T1_TOA")) for flood mapping. I am trying to write the code but I'm stuck at a line where it says "Layer error: Image....
Tanmoy Majumder's user avatar
1 vote
0 answers
81 views

How do I calculate high water extents?

Could someone suggest the right path to follow if I were looking to calculate the high water extents or potential flooding that could occur on a tidal river. I am working in ArcGIS Pro and have ...
Josh's user avatar
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2 answers
307 views

Delete geometries based on intersection with another layer

Working on QGIS, I have two layers 1. buildings (polygons) 2. flood area (polygons) I want to get rid of the building located in flood plains. In other words, I need to find where those layers ...
mbk_wass's user avatar
3 votes
1 answer
479 views

Calculating area in QGIS, defined as zone with relative elevation compared to a river

I’m trying to do the following in QGIS. When creating a 3D map, I want to follow a line or area of interest, such as a river, and create an area which is measured perpendicular to the line of interest,...
quoteunquote's user avatar
1 vote
0 answers
73 views

How to check hydrological connectivity in flood fill techniques in QGIS?

I have a set of polygons (include their elevation levels), representing geographical areas. I want to check which polygons will be inundated if a flat flood level is given. Lets say 1m flood from sea ...
Tharindu Manamperi's user avatar
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406 views

Creating a Cross section of a river

I am using QGIS and HEC-RAS for my project. HEC-RAS needs a file for the river bathymetry. Since I do not have data for river bathymetry, I decided to use the Profile Tool in QGIS to create a river ...
FloodSim's user avatar
0 votes
2 answers
1k views

Flood Analysis in QGIS

I am trying to use QGIS to assess what areas will flood if the river floods a specific height. I have a DEM of the area as well as a vector file of the lines of the river of interest. I cannot get a ...
Connor Stack's user avatar
1 vote
2 answers
450 views

Offset raster boundary by elevation

I've been given a raster with flood elevation limits along a river, it's not a constant flood level so elevations range by ~35m. I need to do an analysis of the impacts if these elevations were 2m ...
CEL-ma's user avatar
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Raster manipulation in ArcGIS - Flood Mapping with HAND

I am trying to create flood maps using the height above nearest drainage (HAND) method using data from the continental flood inundation mapping (CFIM) project. I have the following data: A raster map ...
David B's user avatar
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0 answers
140 views

Measuring the intensity of raster pixels within buffers

I need to create a variable ranging between 0 and 1 to compute the intensity of a flood. I have the raster file for the flood and the layer with the coordinates of the households that have been ...
Sveva Vitellozzi's user avatar
0 votes
1 answer
134 views

Generating extent of 1 ft rise in floodplain using ArcMap

I have a polygon layer that represents the max inundation extent along a stream for the one-year storm event (generated in hec ras). If this floodplain was theoretically raised by one foot, what would ...
Joe G.'s user avatar
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0 votes
1 answer
407 views

What does "slope.lt(5)" do in Google Earth Engine?

Can someone explain what ".lt" is in the code below, and how it works? var hydrosheds = ee.Image('WWF/HydroSHEDS/03VFDEM'); var terrain = ee.Algorithms.Terrain(hydrosheds); var slope = ...
Python Lover's user avatar
2 votes
1 answer
586 views

How to find out which areas are affected by flooding due to heavy rain?

I'm working on a little project to visualize affected streets of flooding due to heavy rain. I already got a DEM for my study area and filled the depressions with r.fill.dir. Since I never worked on ...
junkking's user avatar
0 votes
1 answer
549 views

Using WofE (weight of evidence) in ArcMap

I need to use "weight of evidence" in a project about floodrisk I heard that this model can be implemented in ArcMap but I did not find any videos in YouTube. Can anyone help me?
bita's user avatar
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0 votes
1 answer
112 views

Editing TIN surface by polygon using ArcMap

I'm doing a 2D hydraulic flood study of rivers in a 63 km2 basin. I have a raster of the topography (1x1 meters) that I have passed to TIN using ArcMap. Giving a z=0.3 meters, I get a TIN network with ...
tromen's user avatar
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1 vote
0 answers
170 views

How do I "flood" a terrain in Cesium to represent a high water level

I am thinking about using a plane object to represent a water level by rendering it as a certain height above ground using Cesium. Is there any example code that
P Moran's user avatar
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1 answer
54 views

Spatial join - allocate values from joined polygon based on input polygon

I'm trying to determine population inside Special Flood Hazard Areas. To do this I'm doing a spatial join of census shapefiles with the FEMA National Flood Hazard Layer, using the Boolean field ...
Ron Campbell's user avatar
1 vote
0 answers
42 views

Creating local copy of an online Potential Flood Inundation Map

I am completely stuck, usually I can figure out how to create a local copy of hosted services, but this one I can't seem to get anything to work and any suggestions would be great. Currently I can ...
Matt Richardson's user avatar
0 votes
1 answer
471 views

Google Earth Engine - Blend Sentinel-1 SAR Images?

Does anybody know why I am getting these strips across my Sentinel-1 images and how to fix it? I am using multiple images over Mozambique between January 1st and January 13th. I want to use this ...
skinerdean's user avatar
2 votes
1 answer
150 views

Creating cumulative friction map

I am looking at bottom friction (Manning's n) values in relation to storm surge as large volumes of water flow over a surface. In order to calculate total head loss occurring as water passes from the ...
Carter Rucker's user avatar
1 vote
0 answers
412 views

GRASS GIS: Time series of overland flow from r.sim.water

I am trying to perform an overland flow routing on a large area using r.sim.water in GRASS GIS. I've looked at other answers and made sure to set my computational region to the elevation raster I'm ...
Jay Coulee's user avatar
3 votes
2 answers
400 views

Creating contours based on polyline using ArcMap?

I would like to create a simple floodplain map. I have LiDAR data with 1 meter accuracy. I have clipped it to a small area of interest that my computer can handle processing the LiDAR. I want to ...
sparky's user avatar
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0 votes
1 answer
1k views

Assigning XS Cut Line Attributes like River/Reach Name, Stationing, Bank Lines, etc?

I'm working on a flood inundation project as my research study of my course. I am now assigning XS Cut Line Attribute (after constructing the XS Cut Lines) in HEC-Georas > RAS Geometry > XS Cut Lines ...
Mark's user avatar
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