The Geodesy
The geodesy is the essential reference for the mapping, that’s how the INCT maintains periodically the basic geodetic networks.
The Algerian geodetic network consists of a:
- geodetic network of first order densifed by a network of second order
- Doppler points network
- GPS points network
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GPS antenna-permanent station at INCT |
GPS receiver |
Classical geodetic network: |
Geodesic points of 1 st order: |
Geodesic points of 2nd order: |
- Number of points : 450
- Distance between points: 30 à 45 Kms
- Used material : Theodolite T3
- Observations: by night on projectors 32 round of angle
- Planimetric accuracy: ~ 10 à 15 cm.
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- Number of points : 3291
- Distance between points: 10 à 20 Kms
- Used material : Theodolite T3
- Observations: by day. 08 à 16 round of angle
- Planimetric accuracy : ~ 10 à 20 cm
- Altimetry: geodetic levelling by T3 with joining to the general levelling of Algeria.
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Doppler points network: |
Doppler points: |
ADOS network points: |
- Number of points : 122
- Duration of observations: 03 days
- Used material: JMR Receivers
- accuracy : ~ 10 à 15 meters
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- Number of points: 08
- accuracy : ~ 1 métre
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view an extract
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GPS points network: |
GPS network of zero order: |
Condensing of GPS network : |
- Number of points : 20
- Duration of observations : 07 days
- Software : Bernese 5.0
- Precise orbites: IGS
- Planimetric accuracy: 05 mm
- Altimetric accuracy : ~01 cm
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- Number of points : 1290 (20 à 30 Km) Nombre de points : 1290 ( 20 à 30 Km)
- Duration of observations : 02 hours
- softwares : Winprism and Astech solutions, trimble Geomatics Office, GNSS Solutions
- Orbites : radio-broadacast
- Planimetric accuracy: ~ 02 cm
- Altimetric accuracy : ~ 05 cm
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view an extract |