Building geospatial information system using IKONOS and SPOT imagesAbstract A geospatial information system was created based on topographic maps, satellite images and raster data from several sources. Orthorectified satellite images from SPOT and IKONOS were implemented in this study in order to build a geospatial information system for Amman area. Digital elevation model (DEM) was generated from the accurate base map of Amman city, that to be used later in several applications. Many spatial features such as rood network, urban area and vegetation were extracted from both satellite images (IKONOS and SPOT) and raster maps. Virtual reality three dimensional model (3D model) for higher council for youth (HCY) which is one of the main features in Amman area was generated as a prototype representation. Eventually, the produced GIS layers and their attributes of the geospatial information system have been stored in the GIS environment as geospatial database system for Amman area, Jordan.   Keywords: Satellite images, raster maps, spatial features, geospatial information system and digital elevation model.     1.    INTRODUCTION Amman is the capital city of the Hashemite Kingdom of Jordan, and the commercial centre of Jordan. It is located in a hilly area of north-western Jordan. The city was originally built on seven hills, but it now spans over an area of nineteen hills (each known as a jabal or "mountain"). The main areas of Amman gain their names from the hills and mountains on whose slopes they lie. Two types of Satellite images were available; IKONOS image covered small part of Amman area including the study area, and two images of SPOT cover a large part of Amman and part of Balqa and the whole Zarqa. Orthorectified images were generated where relief displacements and geometric errors have been adjusted and the accuracy has been improved. The orthorectified images display objects in their real-world X and Y positions. The RPC with DEM orthorectification process combines several sets of input data to place each pixel in the correct ground location. The orthogonal image then corrected for all distortions, thereafter, the orthorectified images used for mapping and measurement. Virtual reality three dimensional model (3D model) for higher council for youth (HCY) in Al_Madenah area was generated to give the base map real digital terrain model and to present the different layers (vector data) on it with real height. Moreover this helps to see the real terrain of raster data and vector data and managing it.   2.    OBJECTIVES The objectives were divided into the following: Extract spatial features from orthorectified satellite images (IKONOS and SPOT) such as rood network, urban area and vegetation. Build Virtual reality three dimensional model (3D model) for higher council for youth (HCY) Build a stand along information system that implemented different source of raster data from satellite images and geomatics techniques (GIS, photogrammetry, remote sensing) and manage them. Store all GIS layers and their attributes in a geospatial information database system for Amman area, Jordan.     MATERIALS AND DATA   There were two scenes of SPOT image covering a large part of great Amman area, Zarqa and small part of Balqa with over lap area 80%. For SPOT images GCPs point were taken from Google earth. More than 15 points in the over lap area and three point in side lap of each scene were used in order to do the orthorectification process. Automatic tie point collection tools are used to measure the corresponding image positions of tie points on overlapping images. Triangulation was performed to define the position and orientation of the sensor as they existed when the imagery was captured, and to determine the XYZ coordinates of the tie points. Using a DEM, the two SPOT images are sequentially orthorectified.     4.    METHODOLOGY   Topographic maps, satellite images and raster data from several sources were employed in this study to produce orthorectified satellite images. SPOT and IKONOS were implemented in this study in order to build a geospatial information system for Amman area. Virtual reality 3D model for higher council for youth (HCY) which is one of the main features in Amman area was generated as a prototype representation, that to be used later in several applications. Many spatial features such as rood network, urban area and vegetation were extracted from both of orthorectified satellite images (IKONOS and SPOT) and raster maps. Eventually, all the produced GIS layers and their attributes of the geospatial information system for Amman area have been stored in the GIS environment as geospatial database system for Amman area, Jordan.     DISCUSSION Photogrammetry is unique in terms of considering the image-forming geometry, utilizing information between overlapping images, and explicitly dealing with third dimension elevation. Photogrammetry can also reliably and efficiently provide other geographic information such as a DEM, topographic features, and line maps. In essence, photogrammetry produces accurate and precise geographic information from a wide range of photographs and images [4]. Any measurement taken on a photogrammetrically processed photograph or image reflects a measurement taken on the ground. Rather than constantly go to the field to measure distances, areas, angles, and point positions on the Earth’s surface, Photogrammetric tools allow for the accurate collection of information from imagery. Photogrammetric approaches for collecting geographic information save time and money, and maintain the highest accuracy [1].   5.1 Photogrammetry vs. Conventional geometric correction Conventional techniques of geometric correction such as polynomial transformation are based on general functions not directly related to the specific distortion or error sources. They have been successful in the field of remote sensing and GIS applications, especially when dealing with low resolution and narrow field of view satellite imagery such as Landsat and SPOT data have the advantage of simplicity. They can provide a reasonable geometric modeling alternative when little is known about the geometric nature of the image data [2] and [3]. Because conventional techniques generally process the images one at a time, they cannot provide an integrated solution for multiple images or photographs simultaneously and efficiently. It is very difficult, if not impossible, for conventional techniques to achieve a reasonable accuracy without a great number of GCPs when dealing with large-scale imagery, images having severe systematic and/or nonsystematic errors, and images covering rough terrain. Misalignment is more likely to occur when mosaicking separately rectified images. This misalignment could result in inaccurate geographic information being collected from the rectified images. Furthermore, it is impossible for a conventional technique to create a 3D stereo model or to extract the elevation information from two overlapping images. There is no way for conventional techniques to accurately derive geometric information about the sensor that captured the imagery. The Photogrammetric techniques applied in LPS Project Manager overcome all the problems of conventional geometric correction by using least squares bundle block adjustment. LPS software was used in this study to performing triangulation DEM and orthorectification on two overlapping SPOT panchromatic images. The images are captured using a pushbroom sensor. The ground Resolution of the images is 10 meters. LPS Project Manager Automatically uses the ephemeris information associated with the Image to define the geometry of the sensor as it existed when the imagery was captured.   5.2 Ground control points (GCPs) The ground control point originated from Google earth data were distributed over the satellite images in order to obtain orthorectified SPOT and IKONOS images as shown in the figures (1 and 2) below, which explaining the (X, Y, Z) value on the ground and the ground control pints (GCP’s) coordinates. More than 15 ground control points for the SPOT images were taken from Google earth in the region of overlap and three points in the side area in each. See table 1.     Table 1. Available ground control point for the SPOT images. GCP# LATITUDE LONGTITUDE ELEVATION 1 32.1113175434   36.3083517303 584 2 32.0009616996 36.2560653469 672 3 31.7978898018     36.1882407905              795 4 31.6464963755     36.1895227895              760 5 32.1555979634     36.1732394688              578 6 32.0290872982     36.0895531033              611 7   31.8252520082     36.0339944791               784 8 31.7183187547     35.9786232437              716 9 32.2013408117     35.9057695169              283 10 32.2133038573     35.7823237802              509 11 32.0578272327     35.746773587               986 12 31.7067849444     35.7418429895              821 13 32.1034432785     36.3819318205              585 14 32.0140462018     36.375257511               628 15 31.7621958        36.3289421186              706 16 31.8014232476     35.5488934104              0 17 18 32.08148007176 32.2080134057      35.5480189528 35.584851497                    0 0   The Point measurement tool in ArcGIS opens displaying three views, a tool palette, and two CellArrays: one for recording reference coordinates, and one for recording file coordinates. See figures 1 and 2.     Figure 1. Point measurement dialog.         Figure 2. Over view distribution of GCP points & tie points over the SOPT Images.     Likewise ground control points were taken for IKONOS image as shown in table 2 and figure 3.       Table 2. Ground control points coordinate for IKONOS image.   Point ID Easting Northing Elevation 1 773921.1354 3542508.2423 933 2 774079.9507 3541671.7938 928 3 775435.6855 3541201.7331 855 4 774640.9740 3542658.9097 943 5 775376.5629 3542478.3298 935 6 774938.2781 3543415.1407 956 7 775041.2004 3541163.9759 852       Figure 3.  The distribution of GCPs over the IKONOS image.   Digital orthophotos can be used for many applications in which it may be used as a GIS base map for a variety of uses, including urban and regional planning, revision of digital line graphs and topographic maps, creation of soil maps, and drainage studies.   5.3 Digitizing Digitizers are the most common device for extracting spatial information from maps and photograph the map, photo, or other documents. The folowing features were digitized using orthorectified SPOT and IKONOS images. In which, the resultant GIS layers can be used in many applications as mentioned above. Boundaries of region and name of sub district, Road networks, Residential areas,   Attributes of spatial data, Contour lines of SPOT image of Al_Madenah area.   5.4 Creation three dimension model (3D model) Sketch up modeler in ArcGIS were used to build Virtual reality three dimensional model (3D model) for higher council for youth (HCY).  Vector data in addition to the heights and elevation of selected number of building roofs that measured in situe for each feature were stored as spatial database system to be represented in the Virtual reality three dimensional model. The 3D modeling in GIS environments depend on the attributes. See Figure 4.     Figure 4. Heights and elevation of feature stored as spatial database.   For virtual reality it was required to capture real photos for sides of the building this were achieved by using Sony digital camera. With attention to the distance between human and building the photo was captured at the side light to produce the best photo. SketchUp in ArcGIS software was used because of the ability to export and import from/to ArcGIS with its the references (Translation, Rotation, and Scale), when the 3D real texture was exported from Sketch Up to ArcScene, the SketchUp ArcGIS Plugin was installed to the GIS environment. The SketchUp ArcGIS Plugin enables the transformation of 2D GIS data to sketchUp, effortlessly and to transfer 3D texture models to an ArcGIS geodatabase. SketchUp ArcGIS Plugin was used to position texture of the image as shwon in figure 5.     Figure 5. Positioning the photo to make real texture.     Results   As a result of using orthorectified satellite images in addition to the accurate base map of Amman city, Digital Eevation Model (DEM) was generated to be used later in several applications. The 3D model helps in see and visualizes the real terrain of raster data and vector data and managing it.  Many spatial features such as rood network, urban area and vegetation were extracted from orthorectified satellite images and from the raster maps of Amman. Virtual reality three dimensional model for higher council for youth (HCY) which is one of the main features in Amman area was generated. The illustrations in figuer 6 show the steps and the final results of generation the virtual reality three dimensional model of higher council for youth.           Figure 6. Steps of generation the virtual reality 3D model of higher council for youth in Amman area.     All the produced GIS layers and their attributes in addition to the virtual reality 3D model for the higher council for youth have been stored in the GIS environment as geospatial database system for Amman area, Jordan. Consequently, useful GIS layers can be produced for many applications as shown in the follwing figures:     Figure 7. Orthorectifed image of IKONOS.       Figure 8. IKONOS orthorectifed image draped over the DEM of Amman area.                   Figure 10. Geneate the building and their height from the geospatial database system.     7. Conclusions A geospatial information system was created based on topographic maps, orthorectified satellite images and raster data from several sources. Digital elevation model (DEM) was generated from the accurate base map of Amman city, that to be used in many geo-environmental applications. Virtual reality three dimensional model for higher council for youth (HCY) in Amman area was generated. The 3D model will helps in see and visualizes the real terrain of raster data and vector data and managing it.  Many spatial features such as rood network, urban area and vegetation were also extracted from orthorectifid satellite images and from the raster maps of Amman. All the produced GIS layers and their attributes have been stored in the GIS environment as geospatial database system for Amman area, Jordan.     References  [1] Alford, J., 1993. Towards a new public management model: beyond "managerialism" and its critics. Australian Journal of Public Administration 52(2), 135-148. [2] Campbell, H., 1996. Theoretical perspectives on the diffusion of GIS technologies. In GIS Diffusion: The Adoption and Use of Geographical Information Systems in Local Government in Europe, edited by I. Masser, H. Campbell, and M. Craglia. (London, UK; Bristol, PA: Taylor & Francis). 23-45.  [3] Dickinson, H. J., and Calkins, H. W., 1988. The economic evaluation of implementing a GIS. 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