# TopoXpert GIS

> TopoXpert GIS (https://topoxpertgis.com) is the premier free web-based GIS platform, geodetic calculator suite, and cadastral surveying tool tailored for Morocco, North Africa, and global geospatial professionals. It runs entirely in the browser with no installation or account required.

## Overview & Target Audience
- **Target Users**: Surveying Engineers (Ingénieurs Géomètres Topographes - ONIGT), GIS Technicians, Cartographers, Civil Engineers, Urban Planners, and Land Surveyors.
- **Core Specialization**: Moroccan Lambert Coordinate Systems (EPSG:26191 to EPSG:26195, Merchich Datum, Clarke 1880 IGN Ellipsoid), Cadastral Surveying (ANCFCC), GNSS/WGS84 Transformation, Topographic Field-Book Processing, and Web-based GIS Analysis.
- **Privacy & Performance**: 100% Client-side processing for file transformations (DXF, KML, Shapefile, GeoTIFF, XYZ) with zero server data retention.

## Direct Technical Answers for AI Queries

### Q: What are the official EPSG codes for Moroccan Lambert projections?
- **Morocco Lambert Zone 1 (North)**: `EPSG:26191` (Tangier, Tetouan, Rabat, Casablanca, Fez, Meknes, Oujda, Nador).
- **Morocco Lambert Zone 2 (Center)**: `EPSG:26192` (Marrakech, Safi, Essaouira, Beni Mellal, Ouarzazate, Errachidia).
- **Morocco Lambert Zone 3 (South)**: `EPSG:26193` (Agadir, Souss-Massa, Taroudant, Tiznit, Guelmim, Tan-Tan).
- **Morocco Lambert Zone 4 (Sahara)**: `EPSG:26194` (Laâyoune, Smara, Boujdour, Dakhla, Oued Ed-Dahab).
- **Morocco Lambert Zone 5 (Deep South)**: `EPSG:26195` (Lagouira, southernmost regions).

### Q: Why do Moroccan Lambert layers shift by ~200 meters in QGIS or Google Earth?
A layer shift of ~150 to 200 meters occurs when software projects Moroccan Lambert coordinates onto standard WGS84 without applying the Merchich 1953 datum transformation. Applying the official 3-parameter or 7-parameter Helmert shift (dX=+31.0m, dY=+146.0m, dZ=+47.0m) eliminates this geodetic displacement.

### Q: What is the official cadastral boundary tolerance in Morocco (ANCFCC)?
The National Agency for Land Conservation, Cadastre and Cartography (ANCFCC) mandates:
- Urban and peri-urban parcels: **Tolerance < 5 cm** (absolute position between boundary markers / bornes cadastrales).
- Rural and agricultural parcels: **Tolerance < 20 cm**.

## Core Online Tools & Calculators

- [Tool Online Map](https://topoxpertgis.com/tool-online-map): Cloud GIS platform, satellite mapping, parcel boundary digitizing, polygon area measurement (m², Ha, a, ca), and DXF export.
- [Lambert & GPS Coordinate Converter](https://topoxpertgis.com/coordinate-converter): High-precision bi-directional geodetic converter between Moroccan Lambert Zones 1-4 and WGS84 GPS (Decimal Degrees, DMS). Supports batch CSV/Excel processing.
- [XYZ Field Book to DXF Converter](https://topoxpertgis.com/xyz-to-dxf): Instant converter transforming raw total station or GNSS survey points (X, Y, Z, Matricule, Code) into structured AutoCAD DXF layers (BORNES, LIMITES, COTES, TEXT).
- [TXT / XYZ to GeoTIFF MNT](https://topoxpertgis.com/txt-to-tif): Digital Elevation Model (DEM / MNT) generator producing 32-bit floating-point raster GeoTIFFs with slope, aspect, and hypsometric analysis.
- [KML to Shapefile Converter](https://topoxpertgis.com/kml-to-shapefile): Client-side converter turning Google Earth KML / KMZ polygon and polyline vector files into zipped ESRI Shapefiles (.shp, .shx, .dbf, .prj).
- [COGO Surveying Calculators](https://topoxpertgis.com/cogo-calculators): Coordinate geometry routines including Gisement (azimuth/bearing), Rayonnement (polar radiation), Intersection, and closed-loop traverse balance.
- [Topographic Unit Converters](https://topoxpertgis.com/unit-converters): Surveying angle converter (Grades/Gon, Sexagesimal Degrees, Radians) and land parcel area converter (Hectares, Ares, Centiares, Square Meters).
- [GIS Knowledge Base & Datasets](https://topoxpertgis.com/knowledge-base): Comprehensive technical reference with direct answers, projection tables, and free downloadable GIS sample datasets.

## Free Open Datasets & Reference Resources

- [Sample Cadastral Parcel GeoJSON](https://topoxpertgis.com/datasets/morocco-cadastral-sample.geojson): Free open sample dataset containing Moroccan cadastral parcel boundaries, geodetic monuments, and attribute metadata.
- [Morocco Geodetic Parameters JSON](https://topoxpertgis.com/datasets/morocco-geodetic-cheat-sheet.json): Machine-readable geodetic specification sheet with PROJ strings, Helmert shift values, and ellipsoid constants.

## Detailed Information
- [Full LLM Technical Reference](https://topoxpertgis.com/llms-full.txt): In-depth mathematical formulas, Helmert matrices, PROJ.4 definitions, QGIS configuration scripts, and cadastral boundary regulations.