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I put 4 different layers into my ArcMap document, but only one of them will show up on the map! I should be seeing the other 3 layers as well. When I do a Zoom to layer, I can see one layer, but I cannot figure out how to make the other 3 show up at once on top of each other.

Before I opened ArcMap, I used ArcCatalog where I right-clicked 3/4 of the shapefiles and clicked PropertiesCoordinate systemImport and then clicked on my Trees layer, which has the coordinate system I want the other 3 to have. But when I opened ArcMap the 4 layers did not overlap, nor could I move them above or below each other.

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It seems like someone had the same issue here: forums.esri.com/Thread.asp?c=93&f=1149&t=91668 "The points display correctly but use of the measurement tool gives me a distance of 36,600 meters from the western edge of Nebraska to eastern Ohio, approximately 22.7 miles." –  gis beginner Jun 8 '12 at 4:42
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The question title is perhaps the number 1 FAQ for this site. –  whuber Jun 8 '12 at 13:14
    
Did you try bring the data frame crs as the same as file crs? –  user15528 Feb 25 '13 at 21:10
    
@whuber, number 3 actually: data.stackexchange.com/gis/query/117131/… :) –  blah238 Nov 27 '13 at 21:59
    
Is it possible to have the same x,y coordinates in the same hemisphere for two different locations with the UTM coordinate system? –  user24943 Dec 16 '13 at 1:17

4 Answers 4

You are confusing two different operations dealing with Projections.

  1. Define a projection: You would use this when you have a shapefile or other featureclass, that does not currently have a spatial reference defined when you look at the properties in ArcGIS. You might also use this if you knew based on some observation, that the projection defined for the layer was wrong. This could be due to recognizing that the coordinates of the features were not appropriate for the currently defined projection, or some other clue. This operation simply overwrites the existing projection with a different one that you specify.

  2. Project a featureclass: This tool is used when you have a featureclass with a defined projection, and you want to convert it to a different projection. This will run the appropriate transformation to change the features to the coordinate space of the new projection.

In your question, you state that you have a shapefile that is currently in a Geographic coordinate system or Latitude/Longtude which has units of Decimal Degrees. This means that you have coordinates in the range of Y/Lat = 0 to 90 and X/Lon = -180 - +180. When you bring this shapefile into ArcMap untouched, its projection will be recognized. If you use the measure tool set to miles, ArcMap will calculate the distance correctly.

You then used the Define projection tool, which doesn't convert the coordinates, but simply changes the projection assigned to the shapefile from Geographic to State Plane NAD 83 California Zone 6 Feet. This gives you a shapefile with units in feet. The features in the shapefile did not have their internal coordinates converted, however, so they are still in the range of X = -180 to +180 and Y = 0 to 90. Running the Project tool using the same coordinate system doesn't actually accomplish anything because you have already set your shapefile to this projection with the Define tool. This is why when you use the Measure tool, the distance is dramatically smaller. Essentially, your all the features of your shapefile are now fitting in a distance of 360 feet horizontally and 90 feet vertically.

The proper procedure, to be performed on the original shapefile in the geographic coordinate system, is to use the Project Tool. For the Projection, choose State Plane, NAD 1983 California Zone 6 Feet. The output should be in the proper location and give a correct distance when measured. It should also overlay correctly on any other layers, provided they have a projection defined and that your Data Frame in ArcMap has a projection defined.

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Thank you! I'll be able to give this a try tomorrow :) –  gis beginner Jun 8 '12 at 6:11
    
And thank you for the detail. It really helps! –  gis beginner Jun 8 '12 at 6:11
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You are welcome. I encourage you to read the ESRI help documentation about spatial references and projections. It is pretty detailed and can help make sense of a pretty confusing topic. –  Get Spatial Jun 8 '12 at 6:40
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+1 This is a great answer and deserves plenty of positive votes. Because the question is a FAQ (perhaps the FAQ for our site), I have merged it with another thread dealing with the same issue, hoping this common thread can be a convenient destination for future questions about projections in ArcGIS. –  whuber Jun 8 '12 at 13:13
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@whuber - Thanks. I feel that this is one of the most confusing aspects of GIS and geography in general. It also tends to get short shrift in many education programs, so anything that can be done to provide clarity, is important. –  Get Spatial Jun 8 '12 at 15:56

Although you have set the projection of your 3 other layers by the properties menu in ArcCatalog, you have failed to re-project the data to the proper coordinate system.

Please try the Project tool, located in Data Management ToolsProjections and TransformationsFeature.

This should allow you to create a new feature class that is projected in the correct coordinate system.

If by chance your 3 shapefiles are of unknown coordinate system, please make sure to set the coordinate system (before proceeding with the above Project tool) for these shapefiles to that of their original projection by using the Define Projection tool, located in Data Management ToolsProjections and Transformations.

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Hi! Thank you for the tip but alas that did not work. I opened ArcMap, went to Toolbox -> data management Tools ->Projections and Transformations -> feature -> Project and then for Input dataset: I put the feature class shapefile i want changed. For Output dataset i just changed the name. For Output coordinate system I clicked "import" and put in the shapefile that has a coordinate system I like. Should i not have done this 'import' even in ArcMap (not ArcCatalog)? Finally i was given 3 geographic transformations to choose from but none of them were the one i wanted! Help! Thanks! –  CaliforniaGirl Feb 21 '12 at 21:33
    
There is a slim chance that your 3 shape files are not in the coordinate system that they are actually defined to be (eg. defined as wgs84 but actually nad83 zone 17N). Can you confirm via metadata, or with the original owner? –  Michael Markieta Feb 21 '12 at 21:55
    
Secondly, can you zoom to the layer (one of your 3 shape files that don't line up) and tell me what mouse hover coordinates are displayed in the bottom right hand corner of your ArcMap interface? Also, zoom to layer of the shape file that you are 'importing' the coordinate system from and tell me what mouse hover coordinates are displayed. I want to compare the spatial references. –  Michael Markieta Feb 21 '12 at 21:58
    
From what I know shapefiles are in dif coordinate systems so i am trying to get them into the same coordinate systems and then also the same projections. Maybe I messed up somewhere? –  CaliforniaGirl Feb 21 '12 at 21:59
    
Ok, do you want me to do this before or after I attempt to change the projection through the toolbox? –  CaliforniaGirl Feb 21 '12 at 22:04

This a simple tutorial one can follow to define/transform geographic coordinate system and/or datum in ArcGIs 9.3., starting from a ".csv" file.

  1. Open ArcMap;
  2. In ArcMap, click on “Tools” button located in Main Menu. Choose the following option: “Add XY Data”;
  3. On “Add XY Data” window, click at the browse button to open the “.csv” file which contains geographic coordinates (columns with x coordinate values and columns with y coordinate values) you want to change/transform (from lat. long. or UTM -> to UTM or lat. long.);
  4. Address X and Y fields on “Add XY Data” window with the respectively columns in the “.csv” file;
  5. On “Coordinate System of Input Coordinates” field (still on “Add XY Data window), select the current datum and coordinate system which your input data are associated;
  6. Next, click on “ArcToolBox” button --> go through “DataManagementTools” --> “Projections and Transformations” --> “Feature” --> “Project”;
  7. In “Project” window: i) click on “Input Dataset or Feature Class” field (it should appear as an option the input file, that was opened in step 4). ii) in the field “Output Coordinate System” choose the desired (new) geographic coordinate system and datum to be associated with data;
  8. Click with the mouse right button on the new layer that was created after previous step, and click “Open Attribute Table”;
  9. It will open the window “Attributes of...”. Click on “options” (lower right corner) and next, click on “add field” (it is going to create columns which will be filled in with new coordinates x and y). Chose a name for the column and set “type” field as “Double”. This step requires repetition (for column with x coordinates and column with y coordinates);
  10. Then, go back to “Attributes of…” window and give a right click on the new column name created at the previous step. Select “Calculate Geometry”. Verify if the option “use coordinate system of the data source” is selected. If yes, click “Ok”. If no, change to this option and then click “Ok”;
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Welcome to our site, Andre, and thank you for this contribution! –  whuber Mar 15 '13 at 17:34

I posted an answer here which may help anyone who is having trouble importing/projecting CSV survey data: http://gis.stackexchange.com/a/109619/14731

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