Questions tagged [water]
The water tag has no usage guidance.
28
questions
0
votes
1answer
35 views
Earth Engine calculation of distance between points to nearest water
I have a list of points and I want to calculate the distance between each of them to the nearest body of water larger than n=10 pixels. In other words, for each point, I want to return a number ...
0
votes
1answer
25 views
How to make histogram of NIR band bimodal enough to differentiate water from land in GEE?
I am interested to map water bodies in a desert from swir band of sentinel 2. How I can make a bimodal histogram in GEE . I have one reference water body in scene.
Is it possible to do the same in ...
0
votes
0answers
24 views
DEM water body visualisation (QGIS): extract areas with a min amount of pixels with the same value (= water surface)
I want to create a background map of a DEM (1m spatial resolution) to show the study area.
The study area (Northern Germany) contains many water bodies. I have problems with the visualisation of these ...
2
votes
0answers
42 views
Given a line/shape how to calculate the area that resemble how the US Census Geography's Inland Water is calculated
I am not a US resident so not quite comfortable asking the US Census directly about this, but I'm just curious how the US Census's Inland water geography is derived, i.e. the methodology of what ...
0
votes
0answers
23 views
Linear regression - water column correction
I am curious what the best way is to do a linear regression between depth (y) and b2/b3 radiance (x). My goal is to derive the slope and y-intercept to plug into the equation z = m1*ln(b2/b3) - m0 [m1:...
2
votes
0answers
34 views
Estimating the water coverage area behind a dam
I have a task to estimate the area that will be covered by water when a dam is built in the provided location. The only thing I have is the max water level calculated for the reservoir.
Is that enough ...
0
votes
0answers
15 views
Can anything be inferred if NHD doesn't name a stream but the local municipality does?
Case in point: https://watersgeo.epa.gov/watershedreport/?comid=5781291 It shows up in the NHD as not having a name but I'm pretty sure that the local municipality that that creek is in (City of ...
3
votes
0answers
50 views
Working with the FlowDir in the national hydography dataset
In the National Hydrography Dataset there's a FlowDir field.
According to https://www.townofnewipswich.org/sites/g/files/vyhlif4766/f/uploads/dataset_dictionary.pdf the two possible values for FlowDir ...
1
vote
1answer
117 views
How to remove areas of water from the US census tract map using R/RStudio
I am trying to aggregate all of the census tracts in the United States for analysis and display, including a realistic depiction of water features when zoomed in. I run into memory issues when doing ...
1
vote
0answers
27 views
MapBox Studio: Styling Water in template dataset
I am using MapBox Studio with their own template dataset called Outdoors.
I discovered that categories of waterways can be addressed by classes such as river, stream, stream_intermittent etc. This ...
2
votes
1answer
52 views
Creating new vector which is “inverse” of existing vector (e.g. water surrounding island) in QGIS [duplicate]
I want to create a new vector layer which represents the surrounding water of a particular island I am working with in QGIS. Is it possible to create a water shape based on an "inverted selection&...
0
votes
0answers
24 views
EarthEngine - Create a Clipped Global Surface Water Occurrence Layer
I am looking to create an inland surface water layer using Earth Engine. The JRC Global Surface Water Mapping Layers, v1.2 - Occurrence band is exactly what I want, but as you can see in the attached ...
0
votes
0answers
32 views
False positive results while mapping water bodies
I am a veterinary epidemiology researcher interested to benefit livestock in a desert. As water is an important resource for herders therefore I have become interested to map water bodies.I learned ...
2
votes
3answers
225 views
Generating multiple water level scenarios with only DEM data in QGIS
I want to depict certain water level scenarios (from -0,40mNN to +0,20mNN) by using a two dimensional hypsometric map. Only provided data are DEM-files of the AOI.
I managed to create the hypsometric ...
0
votes
0answers
53 views
How do I draw polygons from aerial imagery?
I will be working on a project to automatically identify ponds from satellite imagery. I have uploaded the basemap into ArcMap 10.7, but I can't create a feature layer to start editing. How do I add a ...
0
votes
0answers
28 views
R SPEI package on waterbalance timeseries for multiple locations with NA's: unexpected data output distribution
I want to use the spei() function in the SPEI package on a waterbalance dataset from 2015-2020 of 99 locations. The waterbalance is calculated out of MODIS PET values (8-day summed to monthly) and ...
0
votes
0answers
79 views
Surface area of waterbodies for multiple location using Google Earth Engine
Using this code, I've extracted surface area of water bodies (for a period of 6 years) from sentinel 1 GRD dataset. But how can I compute water area extent of multiple location and produce chart/CSV ...
3
votes
1answer
433 views
GEE – Smoothing curve of detected water area
I am trying to plot the time series chart of the detected water area by otsu's method in Sentinel-1 images as a smoothed average curve.
I found two approaches to this for the Google Earth Engine:
...
1
vote
1answer
74 views
Techniques to map small water bodies in desert
Techniques to map small water bodies in desert
I have task to map water bodies in a desert. I used landsat 8 and calculated three indices called NDMI, Tasseled Cap Wetness, & AWEIsh. I am ...
0
votes
1answer
112 views
Mapping of small water bodies in desert environments
I am trying to map small surface water bodies in a desert.
My issue is: water pixels don't cover full extent water bodies (see screenshot attached).
What threshold values would I need so that water ...
1
vote
0answers
43 views
Map surface water bodies in a desert
I am interested in mapping surface water bodies in a desert. I have used Tasseled Cap Wetness (TCW) in GEE. After running my code, I found that water bodies (locally called tobas) were not marked. I ...
1
vote
0answers
104 views
Checking if network has connection errors
I have given a network of a city in dwg.
I made a dxf that only contains the network itself, and created a layer for every type of pipe (like 25KPE, 80KPE etc...).
How do I check if the network is ...
1
vote
0answers
84 views
ArcGIS Pro Arcade expression to Maintain line-to-point connectivity
A customer was using a geometric network to maintain connectivity between lines and points. Now they are using ArcGIS Pro, which does not support geometric networks.
They cannot use the Utility ...
1
vote
2answers
940 views
Calculating water occurrence of Sentinel-1 images in Google Earth Engine
I would like to derive the occurrence of surface water bodies from Sentinel-1 image collection in the Google Earth Engine.In my example I could already compute the water mask using Otsu’s method for ...
0
votes
0answers
18 views
Scale national economic data down to a watershed
Economic Input Output databases such as e.g. the World Input-Output Database by the European Commission contain economic (and often environmental) statistics. The spatial resolution of data provided ...
0
votes
0answers
45 views
Creating a “Stream Order” of canal system using ArcMap
I'm interested in creating a "Stream Order" for our canal system. I am the GIS Specialist for an irrigation district. I would like to have the ability to have a layer for when I click on a section of ...
2
votes
0answers
346 views
SVG symbols for water management
I'm searching for SVG of different (german) hydrant types ("Unterflurhydrant", "Überflurhydrant", "Hydrantenschacht") etc.
The symbols are currently stored as polygons in MapInfo's proprietary .TAB (...
1
vote
1answer
317 views
Extract data from osm.pbf with GDAL
I tried osmosis, osm2pgsql, osmfilter, and probably most of OSM related tools in order to extract polygon rivers and water bodies.
Among the tools, OGR is intuitive and returns good results so far
...
