In ArcGIS, I inherited a database of points in a raster image of Mars, each point indicates a crater occurrence. These are around 60,000 points, all of them in a shapefile. Both the raster and shapefile have the right scale, but are not referenced.

I created a georeferenced Mosaic of the same area with updated data, and I'm trying to consolidate both. When I try to export the points it tells me the file does not have a frame of reference (of course).

How should I tackle this problem in ArcGIS for Desktop?

  • 1. Does the baseline raster (the raster you would like to use as a source of projection information) has a projection information? 2. The image and points are you sure they are just missing a projection (not defined) OR is it that they need geo-referencing? depending on the answer the solution is either to use the project raster function or for the latter use the geo-referencing tool to geocode your image to a raster file that has known Maritan reference.
    – yanes
    Dec 4, 2015 at 18:50
  • The baseline raster has all the projection information. And yes, the points also need georeferencing. Dec 4, 2015 at 19:00

2 Answers 2

  • If your data is not geo-referenced to begin with use the geo-reference tool

enter image description here

To geo-reference:

  1. Add the image(layer) that has the correct geo-reference information into your ArcMap,
  2. Add your un-referenced image in your ArcMap
  3. Right-click in the menu area and add the georeferencing tool shown above.
  4. In the layer dropdown menu select your raw-image(not-georeferenced).
  5. Zoom to the baseline image by right-clicking on it and clicking zoom to layer.
  6. from the georeferencing tool (drop-down menu) click Fit to Display ( this will focus the raw image in context to the baseline image, repeat this as many times as you need to align most of the features you want to align visually.You do this by zooming in/out or panning of your baseline image and clicking Fit to Display until the match is acceptable to easily map points between the two layers. The close it is to the scale of the referenced image the easier it is when you do the referencing.
  7. using the Add control points button (second from last in the image above- two +signs connected with a line) start marking areas from the unknown to the referenced layer. Here make sure you select locations (these are called control points) you know are the same as the locations in your geo-referenced image. Always map from the unknown to the known..not the other way round.
  8. Finally, if you are happy with what you see, click on the geo-referencing drop-down menu and select rectify then save your newly rectified image. (depending on the number of control points you have you can select a number of transformation terms. 1st deg, 2nd deg. etc.. polynomial or spline, won't hurt reading upon that as this is not the place to expand on the subject)

NOTE: Your accuracy depends on both the quality and quantity of your control points, However if you have really accurate control points even 4 points (1 at each corner of the image) can give you good result.

here is a geo-referencing video I found on youtube to start with, I haven't watched it to the end. You can also read up on ESRI help on the tool itself.

For your shapefile use the tool suggested by @William.

  • If your data is geo-referenced but you need to re-project it: Use the Project raster tool shown below:

IN the input raster -> your image location, output raster dataset -> your output name, Output Coordinate system -> click on the hand icon and navigate through the 'import' button that appears to find the raster file that you know already has the projection you want to copy, Parametrize the 'Environments' options as necessary and click OK

enter image description here

For the shape file use the project function you find under the Feature group in the projections and transformations toolbox.

  • Thanks, when I try to use that, I get an error, that the current raster has no coordinate system Dec 4, 2015 at 21:48
  • Oh that was why I was asking about geo-referencing on your original post, In that case you need to use the geo-referencing tool. I will update my answer to reflect that. But if you have not done any geo-referencing/geo-rectifying before it is advisable to read on some tutorial first.
    – yanes
    Dec 4, 2015 at 23:07
  • YEs, I'm aware of that, would you have a good link for that. Thanks! Dec 4, 2015 at 23:28
  • I added a link to a youtube video, and step-by-step in the answer. good luck
    – yanes
    Dec 4, 2015 at 23:33
  • Another step by step instruction from Tufts, and another good one here. A good book on map projections in general (focuses on Earth), there might be a free e-book version on the web-somewhere.
    – yanes
    Dec 4, 2015 at 23:43

Use the Georeference tool for the raster Use the Spatial Adjustment tool for the shapefile.

Create some control points to snap to.

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