Latest Contributions by PatriciaDianderas

Hi Melita, Apologize for answer quite late. Look I try many ways and obtain the same result, well I did not use the parameters that they gave me (which we do not know from where it was obtain) not feel conformable using them; however we travelled to meet the originator of the shape files. They are working with a huge amount of information, the point is, that they are working and generating the information in Greek GRID, ALL the information; and then they load it in the server. The quantity information for the server they have is too much, so what the IT department did is "block" the volume of the information we can access though internet: for example in the shp file named as Parcels Zone A, it has more than 10000 features inside, then I open the shape file with my computer I can see the complete shape in the screen but when I open attribute table I am capable only to read 1000 items, if I exported the shape only the 1000 items are exported and they are the 1st 1000 items, I can not access to the other 9000 or selected the part I need, only see them in the screen. So, we saw the original files load in the server (they are in Greek Grid) but immediately when I access to the server (by internet in the web portal) I only have real access of part of the shape, and when I check the layer properties the project system coordinate is changed to WGS_1984_Web_Mercator_Auxiliar_Sphere!!!! Therefore is it possible that when the information is load to the server and access to it through the web the files coordinate system change? Or maybe because the files are (we can say) split to have access only the 1000 items first contributed to change the coordinates and increase the mistake in the accuracy? I really do not know what to do, and how explain to my boss why we have that difference. cheers Pat ... View more

Melita, what I use to do is import the data from the server (that is in WGS_1984_Web_Mercator_Auxiliary_Sphere) then I use the projections and transformation's tool from ArcToolbox, when I introduce the Input dataset or feature class, it automatically recognize de projection(WGS_1984_Web_Mercator_Auxiliary_Sphere) and then I set the out coordinate system in greed grid with the parameters: Greek_Grid WKID: 2100 Authority: EPSG Projection: Transverse_Mercator False_Easting: 500000.0 False_Northing: 0.0 Central_Meridian: 24.0 Scale_Factor: 0.9996 Latitude_Of_Origin: 0.0 Linear Unit: Meter (1.0) Geographic Coordinate System: GCS_GGRS_1987 Angular Unit: Degree (0.0174532925199433) Prime Meridian: Greenwich (0.0) Datum: D_GGRS_1987   Spheroid: GRS_1980     Semimajor Axis: 6378137.0     Semiminor Axis: 6356752.314140356     Inverse Flattening: 298.257222101 and as you can see is the same as the official parameters that the company gave us, and I do not change anything, I do not introduce any information all is done in the program, maybe I am doing wrong and need to know what is that I hope that with this information you can help me, cheers Pat ... View more

HI Melita, The official parameters that they gave me are: GEODETIC PARAMETERS GREECE Grid Projection: Traverse Mercator False Easting:500000.0 False Northing:  0.0 Central Meridian:  24.0 Scale Factor:  0.9996 Latitude Of Origin:  0.0 Linear Unit:  Meter (1,0) Geographic Coordinate System: GCS GGRS 1987 Angular Unit:  Degree (0,0174532925199433) Prime Meridian:  Greenwich (0,0) Datum:  D GGRS 1987 Spheroid: GRS 1980 Semimajor Axis:  6378137.0 Semiminor Axis:  6356752,314140356 Inverse Flattening:  298.257222101 But when I found the differences after the transformation, a college working in other area near the one I am, told me that they solve the problem using this: Transformation Method: Coordinate Frame dx=-203; dy=73;dz=243 rx=0,17;ry=0,06;rz=0,151;s=0,294 So I am trying to find from where they obtain these parameters but until now no answer. I am still lost, and could not explain the difference, all of us are using ArcGIS 10.3 thanks is advance. cheers Patricia ... View more

Ok, I will try to explain better my problem. The original shapes where created in WGS 1984, I do not know why at the moment to share the projection coordinates were changed, so now I have shp files in a server that are in the Projection Coordinate System WGS_1984_Web_Mercator_Auxiliary_Sphere (use in google earth etc), but I have to work with that information in the Greek Grid. When I transform the server shp files to the Greek Grid I have a difference in the position with the original information: 1st I use ArcToolbox/projections for made the transformations and obtain a difference in the in the coordinates with the original shapes, 2nd so I try by other way and export the server shp files using the same coordinate system as the data frame (Greek Grid) and in again obtain the same coordinates, means all are move from the original shapes. If during all these different process we use ArcGIS 10.3 why we have difference in the information? it is possible that any of the parameters in ArcGIS could be wrong? I am trying to find the parameters of the transformation between WGS_1984_Web_Mercator_Auxiliary_Sphere and Greek Grid so maybe creating a custom geographic transformation I can obtain the correct coordinates. Can somebody help me? ... View more