EPSG:6646 — Karbala 1979 / Iraq National Grid
Karbala 1979 / Iraq National Grid (EPSG:6646) — a Projected (metres) system on the a=6378249.145 datum, used in Iraq. Parameters, proj4, WKT, accuracy ±0.1 m, plus a fre…
At a glance
- EPSG
- 6646
- Name
- Karbala 1979 / Iraq National Grid
- Kind
- Projected (metres)
- Family
- Transverse Mercator (belt)
- Ellipsoid
- a=6378249.145
- Accuracy
- ±0.1 m (vs PROJ)
- Countries
- Iraq
Area of use
| West | 38.79° |
| South | 29.06° |
| East | 48.61° |
| North | 37.39° |
Projection parameters
| Projection | tmerc |
| Latitude of origin | 29.0262683333333 |
| Central meridian | 46.5 |
| Scale factor | 0.9994 |
| False easting | 800000 |
| False northing | 0 |
| Semi-major axis | 6378249.145 |
| Inverse flattening | 293.465 |
| Units | m |
| Helmert shift to WGS84 | 70.995,-335.916,262.898,0,0,0,0 |
+proj=tmerc +lat_0=29.0262683333333 +lon_0=46.5 +k=0.9994 +x_0=800000 +y_0=0 +a=6378249.145 +rf=293.465 +units=m +no_defs +towgs84=70.995,-335.916,262.898,0,0,0,0
PROJCS["Karbala 1979 / Iraq National Grid",GEOGCS["GCS_Karbala 1979 / Iraq National Grid",DATUM["D_Custom_6378249.145",SPHEROID["Custom_6378249.145",6378249.145,293.465],TOWGS84[70.995,-335.916,262.898,0,0,0,0]],PRIMEM["Greenwich",0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",800000],PARAMETER["False_Northing",0],PARAMETER["Central_Meridian",46.5],PARAMETER["Scale_Factor",0.9994],PARAMETER["Latitude_Of_Origin",29.0262683333333],UNIT["Meter",1],AUTHORITY["EPSG","6646"]]
Sample conversion
Iraq capital: WGS84 44.36610, 33.31520 → EPSG:6646 601676.063, 477242.630
Values are within ±0.1 m at the test point.
About the Transverse Mercator (belt) family
Karbala 1979 / Iraq National Grid is a Transverse Mercator belt — a national or cadastral grid in metres, conformal (angles are preserved), with its own central meridian and scale factor. Egypt's Red/Purple/Blue belts, the Levant grids, and many Gulf cadastral systems are of this kind.
Two things decide whether your coordinates land correctly: the exact belt (central meridian) and the datum. Mixing a coordinate from one belt into another, or ignoring the datum shift to WGS 84, is the usual cause of a systematic offset in imported survey data.
Related systems
- EPSG:3391 — Karbala 1979 / UTM zone 37N
- EPSG:3392 — Karbala 1979 / UTM zone 38N
- EPSG:3393 — Karbala 1979 / UTM zone 39N
- EPSG:3394 — Nahrwan 1934 / Iraq zone (LCC)
- EPSG:3889 — IGRS
- EPSG:3890 — IGRS / UTM zone 37N
- EPSG:32637 — WGS 84 / UTM zone 37N
- EPSG:32638 — WGS 84 / UTM zone 38N
- EPSG:32639 — WGS 84 / UTM zone 39N
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FAQ
- What is EPSG:6646?
- It is the coordinate system “Karbala 1979 / Iraq National Grid”, a Projected (metres) system in the Transverse Mercator (belt) family, identified worldwide by the code EPSG:6646.
- What datum does it use, and how accurate is it?
- It is based on the a=6378249.145 ellipsoid and it carries Helmert parameters to WGS84. The residual at the test point is about ±0.1 m versus PROJ; for centimetre work use a geodetic adjustment service.
- Where is this system used?
- It is used in Iraq. This page shows its area of use as a coordinate rectangle above.
- How do I convert EPSG:6646 to WGS84?
- Use the free coordinate converter above (preloaded with this system) to convert to WGS84, UTM, or any other system, within a ±0.1 m residual.
You may also need: Arab-world coordinate converter · Surveying file format converter · Batch coordinate file converter