liminfoPrecision Ag Reference
Free reference guide: Precision Ag Reference
About Precision Ag Reference
The Precision Agriculture Reference is a comprehensive, searchable guide to modern precision farming technologies. It covers ISOBUS/ISOXML communication standards, variable rate application (VRA) with prescription maps, remote sensing indices like NDVI and NDRE, RTK-GNSS positioning, yield monitoring and map cleaning, management zone delineation, and farm data exchange formats including Shapefile and GeoTIFF.
Designed for agronomists, agricultural engineers, crop consultants, and precision ag technicians, this reference provides quick access to protocols, sensor specifications, and data workflows used in site-specific crop management. Whether you are setting up ISOBUS task controllers, calibrating yield monitors, or building prescription maps for variable-rate fertilization, this cheat sheet has the details you need.
All content is organized into categories such as ISOXML/ISOBUS, Variable Rate, Remote Sensing/Sensors, Yield Map, Data Formats, Automation, and Soil/Nutrition. Browse from any device with full dark mode support, entirely in your browser with no data uploaded to any server.
Key Features
- Complete ISOBUS/ISOXML (ISO 11783) protocol reference with TaskData XML structure and Task Controller versions
- Variable rate application (VRA) guide including prescription map creation and section control setup
- Remote sensing vegetation indices — NDVI, NDRE formulas with satellite and drone resolution specs
- RTK-GNSS accuracy comparison from standalone GPS to cm-level RTK positioning
- Yield monitor calibration, yield map data cleaning, and management zone delineation methods
- Farm data format reference for Shapefile, GeoTIFF, ADAPT framework, and FMIS platforms
- Automation coverage including auto-steer guidance, UAV drone applications, and IoT soil sensors
- Soil sampling strategies with grid-based and zone-based approaches for nutrient mapping
Frequently Asked Questions
What precision agriculture topics does this reference cover?
This reference covers ISOBUS/ISOXML communication standards, variable rate application (VRA) with prescription maps, remote sensing indices (NDVI, NDRE), RTK-GNSS positioning, yield monitoring and map cleaning, management zone delineation, farm data formats (Shapefile, GeoTIFF, ADAPT), auto-steer guidance, agricultural drones, IoT soil sensors, weather stations, and soil sampling strategies.
How does variable rate application (VRA) work?
VRA adjusts input rates (fertilizer, seed, pesticide) based on location within a field. A prescription map defines different zones with specific application rates. The map is loaded into an ISOBUS-compatible task controller, which communicates with the applicator to vary rates as the machine moves across the field. Real-time sensor-based VRA using NDVI sensors is also supported.
What is the difference between NDVI and NDRE?
NDVI (Normalized Difference Vegetation Index) uses NIR and Red bands and is the most common crop vigor indicator. NDRE (Normalized Difference Red Edge Index) uses NIR and Red Edge bands, which makes it less prone to saturation in dense canopies and more sensitive to nitrogen status. NDRE is preferred for mid-to-late season nitrogen management decisions.
How accurate is RTK-GNSS for precision agriculture?
RTK-GNSS provides 2-3 cm accuracy, which is essential for auto-steer systems and precision seeding. By comparison, standalone GPS provides 2-5 m accuracy and DGPS provides 30-50 cm accuracy. RTK requires a base station and rover configuration, often using NTRIP correction services delivered over the internet.
What is yield map cleaning and why is it important?
Yield map cleaning removes erroneous data points caused by harvest start/end delays, zero or excessive speeds, swath width mismatches, and statistical outliers. Without cleaning, these artifacts create false spatial patterns that lead to incorrect management zone boundaries and inaccurate prescription maps for the following season.
What data formats are used in precision agriculture?
The main formats are Shapefile (.shp/.dbf/.shx/.prj) for vector spatial data, GeoTIFF for georeferenced raster imagery from satellites and drones, and ISOXML for machine-readable task files. The ADAPT framework from AgGateway provides a middleware layer for converting between vendor-specific proprietary formats.
How are management zones created?
Management zones are delineated using input layers such as multi-year yield maps, soil EC maps, DEMs, and NDVI imagery. Statistical methods like k-means or fuzzy c-means clustering group similar areas. Typically 2-5 zones are created per field, and the results are validated using ANOVA to confirm statistically significant differences between zones.
Is this reference free to use?
Yes, this precision agriculture reference is completely free with no usage limits, no account required, and no software installation needed. All content is rendered client-side in your browser, and no data is sent to any server.