Monday, November 20, 2017

Photogrammetry Dept

The following nationwide projects are addressed here.

 

·         Topographic Base Map Compilation at the scale of  1:25,000  

This project was started in 1991 using analogue technology and then switched to digital products. Maps of border areas were produced by using satellite imageries due to the security problems of aerial photography. SPOT5 HRG satellite images together with SPOT5 HRS DEM have been used in this respect. More than 9600 digital map sheets, covering 95 percent of the whole country, have been produced by the end of Sept. 2009. It is expected that the whole country of Iran will be completed by the end of 2011. It should be mentioned that the country has been divided to about 132 blocks with dimension of 1.5 degree in longitude and 1 degree in latitude.

Besides map compilation, revision of existing maps has already been started and so far some 1300 map sheets have been updated. It should be stated that, the high resolution satellite images now seem very appealing for this purpose.

 

·         1:2000 Scale Digital Map Compilation for the Cities of the Country

The demand for reliable and updated large scale maps of cities has been increasing by the governmental and private organizations. NCC is a responsible organization for producing maps of 1026 cities, in cooperation with private sector, in Iran. Digital maps of about 721 cities have been produced so far. It is planned to complete this project within 2 years. Obviously, the updating process has been started during the report period. Total number of 3200 map sheets has been produced by the end of Sept. 2009.

  

·         Image Maps & Digital Elevation Models (DEMs)

Thanks to the availability of high resolution satellite imageries coupled with access to fast computers and comprehensive processing software packages, there has been a revolutionary increase in demand for different types of image maps in Iran. For example, more than 130 large and medium scale image mapping projects have been performed by NCC and private companies in 2007.

Digital Elevation Model is a key element of image mapping and remote sensing activities. Hence, a national DEM based on 1:25,000 base map series with 10m resolution has been produced. At present, more than 90 percent of country is covered with these DEM data with height accuracy better than 6 meter. At present time, some programs for improving this data in terms of accuracy and resolution are under progress.

Geo-referenced and geometrically corrected image data are required in order to promote remote sensing activities. For this purpose a pilot project was executed with a full coverage of Landsat ETM+ imageries for the whole country of Iran. It went through a rectification process using 1:25.000 base maps and 10m DEM of Iran. The final products were presented as ortho-rectified 14m PAN and 28.5m multispectral satellite imageries in a block wise manner in 2004.

 The next project with the same perspective was started at nearly the same time. This project uses the IRS1C/1D 5.8 m resolution satellite data and the produced map sheets are in the same size of 1:50,000 scale map sheets. About 3000 orthorectified image map sheets have been produced so far.

 


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