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I have some prj files (Only prj) but don't know how to open them, I tried ArcMap but have no clue. I understand prj is a part of a shapefile, but I don't have any other files than these.

PolyGeo
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1 Answers1

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Right click and open with a text editor like notepad (or Notepad ++). It's not a GIS layer, just some projection metadata on your layer.

A shapefile is made of severall files with some mandatory. The prj is not one of them. You'll need to ask for the mandatory ones... :

Mandatory files

  • .shp — shape format; the feature geometry itself
  • .shx — shape index format; a positional index of the feature geometry to allow seeking forwards and backwards quickly
  • .dbf — attribute format; columnar attributes for each shape, in dBase IV format

Other files

  • .prj — projection format; the coordinate system and projection information, a plain text file describing the projection using well-known text format
  • .sbn and .sbx — a spatial index of the features
  • .fbn and .fbx — a spatial index of the features that are read-only
  • .ain and .aih — an attribute index of the active fields in a table
  • .ixs — a geocoding index for read-write datasets
  • .mxs — a geocoding index for read-write datasets (ODB format)
  • .atx — an attribute index for the .dbf file in the form of shapefile.columnname.atx (ArcGIS 8 and later)
  • .shp.xml — geospatial metadata in XML format, such as ISO 19115 or other XML schema
  • .cpg — used to specify the code page (only for .dbf) for identifying the character encoding to be used
  • .qix — an alternative quadtree spatial index used by MapServer and GDAL/OGR software

Source : Wikipédia

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gisnside
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  • This is one reason plain text is superior to binary whenever it's practical. – jpmc26 Jan 17 '18 at 01:35
  • if i open it with notepad it says: ÂH;V ŒÄ? tTà‹«?Œ´cÂHÛ?øâê e?.qê÷Üç?¶›åIdŠ?š™™™™™é?©ÀW?èØ?ð¹%Nýžë?/®~ÐQé?ê÷ܧ~ß?Ó°Ý,O"ë? „‘v¬@¸?ë øâê?AiÇ „Á?è¨ÀW?à?2 – Puma Jan 18 '18 at 16:47
  • That is very strange, it doesn't look like a prj file to me. Could you upload on of your files on some website for us to test it ? It shouldn't be a heavy file. What's it's size by the way ? – gisnside Jan 19 '18 at 07:12
  • Here is the link for it: https://www.file-upload.net/download-12931703/PrjFile.zip.html Its size is 1 kb – Puma Jan 19 '18 at 16:31
  • Could you rather use https://wetransfer.com/ ? The link you gave me links out to a suspicious exe file of 500Kb or to some adverts... Many thanks. – gisnside Jan 19 '18 at 20:46
  • You have to press the blue "Download" button, then a new tab open and then press the blue button again and it will download automatically? – Puma Jan 20 '18 at 16:49
  • Thanks it worked. I've no idea what this thing is, but it's sure not a prj file. You should definitively ask for other files. Your prj should look like : PROJCS["British_National_Grid",GEOGCS["GCS_OSGB_1936",DATUM["D_OSGB_1936",SPHEROID["Airy_1830",6377563.396,299.3249646]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",400000.0],PARAMETER["False_Northing",-100000.0],PARAMETER["Central_Meridian",-2.0],PARAMETER["Scale_Factor",0.999601272],PARAMETER["Latitude_Of_Origin",49.0],UNIT["Meter",1.0]]. – gisnside Jan 20 '18 at 17:05
  • But it is a prj file or something like that. Because i have a game and there is a map of many countrys. So if i click on germany, it shows the map of germany and i can set a point on the map. And the prj file tells this game "Hey, the upper limit of the map 55 N And in the south its 47 N". So every country has a prj file for itself. – Puma Jan 20 '18 at 17:55
  • And i got no idea, how can i create a prj file or coordinate system in ArcGis, the manual is to complicated for me. – Puma Jan 20 '18 at 18:23
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    This is definitively NOT A PRJ FILE FOR ARCGIS... nor any GIS known to me. Maybe the software / game you are talking about and that you didn't mention has it's own prj file format but I doubt you will find the info here if it's not a GIS software. If you have a question regarding a game or another software, please be precise in your question. I answered your question regarding arcgis desktop. Please ask another question if you need to create a prj file for your data or a specific software. – gisnside Jan 21 '18 at 07:12
  • Yes, then my question is , how can be a prj file created similar to mine? So that is shows a coordinate system for a country. Maybe the prj you send me works,if i fill in the right numbers. What would them be for Germany? – Puma Jan 21 '18 at 15:28
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    You should create a new question, and maybe look if the question hasn't been asked before (example : https://gis.stackexchange.com/questions/219334/how-to-create-prj-file-for-selfmade-polygons-in-arcmap or https://gis.stackexchange.com/questions/237770/what-is-a-projection-for-germany-that-preserves-distance). – gisnside Jan 21 '18 at 16:56