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Landuse/landcover Mapping of Centeralwater shed of iran based on Satellitte data Interpretation
Geology:
By inspection, the tectonic map of Iran indicates that the centeral watershed is composed of the three geological groups: ingneous metamorphic and sedimentary.
Most of the region is covered by sedimentary deposits, conglomrates and evaporits of the centeral Iranian Depression. These deposits are overlain by volcanic rocks and tuffs. The volcanic types are associated with the alborz mountain range and the mountian range running parallel to the zagros mountains between Arak and Qum.
The area where the Zagros mountain range surrounds the inner plateau is generally described as sedimentary, with slight metamorphism.
A small area north-east of Golpayeagan also displays metamorphism. The marked salinity within the region results primarily because the evaporation potential exceeds precipitation. This is evidenced by the runoff that flows into the in land basins. The flows subsequently evaporate, Leaviny a residue of salt concentrates. In addition a number of salt plugs increase the salinity of the natural runoff.
In this area seven physiographic units have been recognized. These are:
Mountains-Hills-Plateau and upper terraces, Pied mont plains, river Plains-Lowland- flood Plain- Alluvial Fans Plains- Colluvial Plains- Sanddune.
Results and Analysis
Landuse/Land cover map of the centeral watershed which is exhibited at a scale of 1:1000,000, based on data analysis and interpretation of available landsat data.
In this area, seven major units have been recognized as follows:
1- Urban or built-up Lands:
This unit consists of residential, industrial, commercial area and major transportation and communications.
2-Agricultural Lands:
This area consists of predominately irrigated croplands, Dry farm croplands,Orchard, Vine yards that occur predominantly in plains, arround the residential area, along the rivers, gentely slop in hills.
3- Range Lands:
This area consist of high, medium,Low,Poor production range lands that mainly occuring on the mountains, hills and plains,
4-Forest Lands:
There is low density forests in this watershed because of it low rain fall.
This unit occur only in south of Alborz peidmont.
5-Water:
This unit consists of the main natural drainage and four reserviors.
6-Wet Lands:
This area cover by permanent and temporary salt water that consists of shrubs and nonshrus wet Lands.
Mainly ocuring in the lowland areas.
7-Barren Lands:
Most of this area located on arid parts of watershes. It consists of salt flats and Playas, sandy area, bare exposed rock.
Conclustions and Recommendations
The following conclusions and recommendations obtained from results and analysis:
- To achieve accurent and desirable results, the interpreters should be well informed about the genetal geography conditios of the area and also be familiar with existing land form.
- There should be a logical relation between level of study and the chosen scale.
- Using of imagery prepared in spring and autumn is more suitable for Landuse/Land cover Mapping, but using imagery prepared at different times of the year could be useful in interpretation of data.
- Its better that the selected images should have uniform colour tons as well as good quality so that folowing and Landuse units from one image to another is smooth.
- The accuracy interpretation for the several categories should be about equal.
- Utilization of all available data and field control is important and for interpretation and accuracy for landuse/land cover mapping.
- Available and standards classification system according to the natural characteristic of the country is necessary.
Table : Areal coverage of the various land use/land cover units in the centeral watershed.
| NO | UNIT | AREA OF COVERAGE (SQUARE Kms.) | PERCENTAGE |
| 1 | Urban for built –up lands | 540.6 | 0.56 |
| 2 | Agricultural lands | 25518.2 | 27.69 |
| 3 | Range Lands | 48473 | 52.61 |
| 4 | Forest Lands | 71.4 | 0.08 |
| 5 | Wet Lands | 6399.7 | 6.95 |
| 6 | Barren Lands | 11122.1 | 12.08 |
| | Total: | 92125.0 | 100.00 |
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