What is Ground Sample Distance (GSD) and how do I calculate it?

Ground Sample Distance (GSD) is the real-world distance represented by a single pixel in an aerial image. Formula: GSD (cm/px) = (Flight Altitude × Sensor Width × 100) / (Focal Length × Image Width in px). GeoProTools calculates GSD instantly with the Quick GSD bar at the top of the page.

How do I convert UTM coordinates to Geographic (Latitude/Longitude)?

In GeoProTools, select 'UTM → Geographic' from the Geodesy menu. Enter the Easting (E), Northing (N), and UTM Zone (e.g., 23S). The tool uses Proj4js with the selected datum (WGS84, SIRGAS2000, NAD83 and 20+ others) to convert to decimal degrees and DMS format instantly.

What is magnetic declination and why is it important for surveying?

Magnetic declination is the angle between magnetic north (compass) and true geographic north. It varies by location and time. For topographic surveys, knowing declination is essential to correct compass readings. GeoProTools provides real declination via NOAA World Magnetic Model (WMM) API and an analytical approximation, both with value and direction (East/West).

What is the difference between a closed traverse, bounded traverse, and open traverse?

A Closed Traverse starts and returns to the same known point, allowing full closure error verification with Bowditch compensation. A Bounded Traverse starts at one known point and ends at a different known point (useful for linear infrastructure). An Open Traverse starts at a known point and ends at an unknown point — no closure check is possible, so it is only suitable for reconnaissance surveys.

How do I export UTM coordinates to KML for Google Earth?

In GeoProTools, open the 'UTM → KML/KMZ' tool under the Geodesy menu. Upload a CSV or TXT file with your UTM coordinates (ID, Easting, Northing, Altitude columns), select the UTM zone, datum, layer name, geometry type (points, polygon, or linestring), and click Generate KML. The file opens directly in Google Earth, QGIS or ArcGIS.

What drone flight conditions does GeoProTools analyze?

GeoProTools Drone Flight Indices tool queries real-time meteorological data from the Open-Meteo API and analyzes: wind speed and gusts (m/s), UV index, cloud cover (%), visibility (km), precipitation (mm), K-Index for atmospheric convectivity, recommended mission speed, front/lateral overlap, mission GSD, and overall flight aptitude rating.

Is GeoProTools free to use?

Yes. GeoProTools is completely free, with no registration required. All tools — GSD calculator, UTM converter, traverse calculation, leveling, KML export and drone indices — are available immediately in English, Portuguese and Spanish.

Which geodetic datums does GeoProTools support?

GeoProTools supports 20+ datums including WGS84, SIRGAS2000, SAD69, Córrego Alegre, NAD83, NAD27, ETRS89, ED50, RGF93, OSGB36, Pulkovo 1942, Tokyo, JGD2000, GDA94, GDA2020, Cape, Hartebeesthoek94, RD New, MAGNA-SIRGAS, and GRS80. Select the active datum in the header dropdown.

GeoProTools – Free Topography & Geodesy Tools

🛩 Photogrammetry

Ground Sample Distance

Calculates the spatial resolution (cm/px) of aerial images obtained by UAV/Drone from sensor and camera parameters.

Flight Altitude (m)

Focal Length (mm)

Sensor Width (mm)

Image Width (px)

Awaiting parameters...

🛩 Photogrammetry

Flight Indices — Drone/UAV

Check meteorological conditions and operational indices for mission planning. Enter coordinates to get real-time data.

Latitude (decimal degrees)

Longitude (decimal degrees)

Mission Altitude (m AGL)

Max Drone Speed (m/s)

Flight Condition Status

💨 Wind

—m/s

aguardando

💥 Gust

—m/s

aguardando

☀️ UV Index

—

aguardando

☁️ Clouds

—%

aguardando

👁 Visibility

—km

aguardando

🌧 Precipitation

—mm

aguardando

Índices Calculados

📊 K-Index

—

convectividade atmosférica

🔲 Overlap

—%

frontal/lateral

⚡ Mission Speed

—m/s

recomendada

🟢 Flyable

—

calcule os índices

📷 Mission GSD

—cm/px

com alt. informada

⏰ Ideal Time

8h–16h

luz solar adequada

🌍 Geodesy

UTM → Geographic Coordinates

Converts UTM plane coordinates (SIRGAS2000/GRS80) to WGS84 latitude/longitude.

Easting — E (m)

Northing — N (m)

UTM Zone

Awaiting parameters...

🌍 Geodesy

Geographic → UTM

Converts WGS84 latitude/longitude to UTM SIRGAS2000 plane coordinates.

Latitude (decimal degrees)

Longitude (decimal degrees)

UTM Zone (optional)

Awaiting parameters...

🌍 Geodesy

Geodesic Distance

Calculates the great-circle distance (Haversine) between two points on the ellipsoidal surface.

Point 1

Latitude 1 (°)

Longitude 1 (°)

Point 2

Latitude 2 (°)

Longitude 2 (°)

Awaiting coordinates...

🌍 Geodesy

Magnetic Declination

Calculates real magnetic declination via NOAA/WMM (World Magnetic Model) and analytical approximation. Both indicate value and direction (E/W).

Latitude (decimal degrees)

Longitude (decimal degrees)

Altitude (m — optional)

Year (current if empty)

Enter lat/lon and choose calculation method.

🌍 Geodesy

UTM Scale Factor

Calculates the UTM linear scale factor, projection scale factor and combined scale factor for a given position and altitude.

Latitude (°)

Longitude (°)

Orthometric Altitude (m)

UTM Zone (optional)

Awaiting parameters...

📐 Topography

Analytical Azimuth Calculation

Determines the planimetric azimuth between two points in the plane coordinate system (E, N).

X1 — Easting (Origin)

Y1 — Northing (Origin)

X2 — Easting (Target)

Y2 — Northing (Target)

Awaiting coordinates...

📐 Topography

Radiation — New Coordinate

Calculates the position of a point by radiation from azimuth and horizontal distance.

X — Station Easting

Y — Station Northing

Horizontal Distance (m)

Azimuth Format

Decimal Degrees

Awaiting parameters...

📐 Topography

Traverse — Survey Walk

Select the traverse type, configure the angular reading mode and enter field data. Direct/Reverse support and 360°/400g systems. Automatic Bowditch compensation.

① Traverse Type

⊙

Closed

Closed Traverse

Returns to origin. Full angular and linear closure error verification.

⊣⊢

Bounded

Bounded Traverse

Starts and ends at different known-coordinate points. Ideal for linear infrastructure.

⊸

Open

Open Traverse

Ends at unknown point. No closure check — for expeditious surveys only.

② Control Points

③ Angular Reading Mode

○ Single Reading

④ Angular System

360° Degrees LI = LD ± 180°

⑤ Traverse Sides

Selecione o tipo, preencha os dados e clique em Calcular.

🌍 Geodesy

UTM → KML / KMZ (Google Earth)

Upload a UTM coordinate table (CSV, TXT or Excel-compatible) and convert to KML or KMZ for viewing in Google Earth or any GIS.

① Conversion Settings

Fuso UTM

Tipo de Geometry

Layer Name

Point Color

② Input Data

📄

Clique ou arraste o arquivo aqui

Formatos: .csv | .txt | .tsv

💡 Formato esperado: Colunas separadas por vírgula, ponto-e-vírgula ou tab.
Colunas detectadas automaticamente: ID/Nome, Easting(E), Northing(N), Altitude(Z)
Exemplo: P1; 558123.456; 8560234.789; 100.0
A primeira linha pode ser cabeçalho — será ignorada se não for numérica.

Configure a conversão, importe os dados e clique em Gerar.

📐 Topography

Leveling & Check-leveling

Enter direct and check-leveling elevations, calculate closure error, proportional distribution and export results as .txt.

① Leveling Points

Initial BM elevation (m)

Final BM elevation (m)

② Direct Leveling

Ponto	Ré (m)	Vante (m)

③ Check-leveling (Reverse)

Ponto	Ré (m)	Vante (m)

Fill in the data and calculate.