Hydrology Analysis

ROOTPIXIN

Study area

Upload your own study area KML. It becomes the area every later step is clipped to.

Upload study area KML

Uploading zooms the map to your study area.

Elevation model

The DEM is fetched automatically for your study area from online SRTM/ASTER-based terrain tiles (30 m or finer). You can still open your own GeoTIFF (lat/lon, EPSG 4326).

Or open a DEM GeoTIFF from this computer

Waiting for the DEM.

Run analysis

Fills sinks, derives flow direction and accumulation, then extracts the drainage network, watersheds and basin measures in one pass.

Stream starts above 0.50 km² of upslope area Contour interval (m)

Load a study area and a DEM first.

Layers and colours

Turn any result on or off, and set its colour right beside it. Colours carry through to the composed maps, the report and the KML exports.

Reference

Study area outline

Place labels

Terrain

Elevation

Hillshade

Slope

Contours

Drainage network

Flow accumulation

Flow direction (D8)

Flow direction arrows

Drainage network

Drainage order (Strahler) — colour by order

Drainage line smoothing

Drainage density surface

Drainage density window radius 1.0 km

Wetness

Wetness index (TWI)

Raster opacity

Catchment at a point

Click anywhere on a stream to trace everything draining to that point. The tool snaps to the nearest channel.

No catchment traced.

Catchment layers

Delineated catchment

Multiple catchments

Outlet point

Multiple catchments for the whole study area

Drainage units — watershed analysis

Splits the whole study area into drainage units. Major basins drain to the area edge; sub-watersheds break those at every stream confluence. The units are part of the drainage network and are drawn and legended with it.

Ignore units smaller than 0.25 km²

No drainage units delineated.

Show on the map

Drainage units (watersheds)

Drainage units (the sub-basin polygons) are separate from drainage order (the Strahler classes of the channels in step 4) — renaming or hiding one never changes the other. Use the palette box for the colour set and the tag button for map labels.

Morphometric parameters

Classic basin morphometry worked out from the same figures as Measurements: stream order and bifurcation ratio, drainage density, stream frequency and length of overland flow, basin shape (form factor, circularity and elongation ratios) and relief (relief ratio, ruggedness number, hypsometric integral). It follows the scope used in Measurements, the whole study area or the traced catchment.

Buffers

Build one buffer or a set of nested rings around the drainage network, a catchment or the study area. Distances are measured to the actual lines, so even narrow buffers stay continuous, and every band carries its own area and can be exported.

Drainage buffers

Buffer around Buffer style

Buffer distance (m)

Draw rings as separate bands

No buffers built.

Rainfall

Bring in rain gauges with one or many time periods, then spread them across the study area with inverse distance weighting, ordinary kriging or Thiessen polygons. Every period can be interpolated in one pass and summarised per drainage unit.

Show all rainfall on the map (gauges and surface)

Rainfall layers

Rainfall surface

Rain points

Colour changes apply at once to the map, composed sheets and the report.

Open a rain gauge CSV

One row per gauge. Header needs name,lon,lat and then one column for every time period, for example name,lon,lat,Jun,Jul,Aug. Values are read as millimetres.

Auto rainfall — free, no sign-up

Pulls real daily rainfall from Open-Meteo's open historical archive (no account, no API key, no cost — needs an internet connection) for one point and date range, totals it by month, and adds it to the gauge list above like any other gauge.

Fetch at

Latitude

Longitude

From

Needs an internet connection — fetches from api.open-meteo.com.

Time period shown Interpolation method

Distance power 2.0

Interpolate every period at once

No gauges loaded.

Flood analysis

Maps flood depth with the HAND method: a cell floods when it lies lower than the water level above its nearest channel. Use a stage you choose, or derive one from a design storm.

Water level from

Flood stage (m)

Height measured above channels of Strahler order 1 and above

Show flood layer

Run the analysis first.

Land use / land cover

Upload a classified LULC KML (each placemark's name, folder or a "class"/"lulc" field is read as its land-cover class). Every class is coloured on the map, and the table below is where you enter whatever extra data your runoff method needs for that class — curve number, runoff coefficient, Manning's roughness, or anything else.

Open a LULC KML

No LULC file loaded.

Show LULC map

LULC fill opacity 65%

Add generated features to LULC

Adds the drainage network and/or the drainage buffer bands you generated as extra classes in the table below, drawn over the land cover (they take priority where they overlap). Give each its own CN / C / n there.

Drainage network (channels)

Channel width (m)

Drainage buffer (built in step 8)

Nothing added.

Runoff map

Turns rainfall into a runoff depth map, cell by cell. Rainfall can come from the interpolated map (IDW, kriging or Thiessen, step 9) so every cell gets its own rain, or from one design rainfall. Land cover (step 11, including any drainage or buffer classes you added) sets each cell's curve number or runoff coefficient.

Rainfall used Runoff method Curve number used where land cover gives none

Show on the map

Runoff depth

Choose the rainfall and method, then calculate.

Measurements

Map composition

Lay out a finished cartographic sheet — graticule frame with latitude and longitude, scale bar, north arrow and a complete legend — then save it as an HD PNG or a print-ready PDF. The same style is used for every figure inside the PDF and Word report.

Map title Subtitle Sheet style Accent colour (frame, titles, rules)

Use this style for the report figures too

Base raster

Layers on the sheet

Terrain

Hillshade

Contours

Drainage network

Drainage network labels

Flow direction (D8)

Flow direction arrows

Drainage units

Drainage unit labels

Drainage buffers

Rainfall

Rain gauges

Rain gauge labels

Flood depth

Land use / land cover

LULC classes

Catchments and reference

Traced catchment

Multiple catchments

Outlet points

Study area outline

Graticule and ticked neatline

Frame the sheet on Margin around the feature 6%

North arrow

Scale bar

Legend placement

Text style — font size & colour, section by section

Map title

Subtitle

Legend heading

Legend text

Scale bar text

North arrow letter

Graticule coordinate labels

Credits line

Page

Print quality

Run the analysis to compose a map.

Report

Writes a discussion of your results in plain paragraphs and lays composed maps between the sections, then saves it as PDF or Word. The figures use the sheet style, accent colour, north arrow, scale bar and legend placement you set in step 14.

Report title Prepared by Notes to include (optional)

Sections to include

Introduction and data

Relief and slope

Drainage network

Flow direction and drainage density

Drainage units

Rainfall

Land use / land cover and runoff

Buffers

Basin shape and runoff

Practical implications

Method and limitations

Measurement table

Maps to compose into the report

Terrain and contours

Slope

Drainage and flow accumulation

Flow direction

Drainage density

Drainage units

Rainfall

Land use / land cover

Runoff depth

Flood depth

Buffers

Wetness index

Traced catchment

Multiple catchments

Map quality in the report Depth of discussion

Run the analysis to build a report.

Downloads

Everything is clipped to the scope you choose. KML opens in Google Earth, QGIS and ArcGIS; the grids open as raster layers.

Clip downloads to

Vector (KML)

Grids

Tables and maps

Run the analysis to enable downloads.

Designed & developed by Dr. Panda

Click a stream to trace its catchment.

Legend

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