# S5 - Age determination through crater counts on Lunar geological maps

**URL:** <https://openplanetary.discourse.group/t/s5-age-determination-through-crater-counts-on-lunar-geological-maps/434>\
**Category:** GMAP-PLANMAP 2021\
**Tags:** arcgis, moon\
**Created:** [February 4, 2021, 9:05am UTC](https://openplanetary.discourse.group/t/s5-age-determination-through-crater-counts-on-lunar-geological-maps/434 "2021-02-04T09:05:01Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![RElbertsen](https://avatars.discourse-cdn.com/v4/letter/r/e68b1a/32.png) [@RElbertsen](https://openplanetary.discourse.group/u/RElbertsen)\
**Post date:** [February 4, 2021, 9:05am UTC](https://openplanetary.discourse.group/t/s5-age-determination-through-crater-counts-on-lunar-geological-maps/434/1 "2021-02-04T09:05:01Z")

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Hi,

Once I click ‘Start edit’, the crater tool becomes active. However, The button ‘Trace’ to edit the area stays inactive. What am I doing wrong?

Thanks,

Rens

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**Author:** ![Claudia](https://avatars.discourse-cdn.com/v4/letter/c/a88e57/32.png) [@Claudia](https://openplanetary.discourse.group/u/Claudia)\
**Post date:** [February 4, 2021, 9:50am UTC](https://openplanetary.discourse.group/t/s5-age-determination-through-crater-counts-on-lunar-geological-maps/434/2 "2021-02-04T09:50:02Z")

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In the newly opened create feature window on the right select the shape that you want to work on. the trace button should now be active

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**Author:** ![RElbertsen](https://avatars.discourse-cdn.com/v4/letter/r/e68b1a/32.png) [@RElbertsen](https://openplanetary.discourse.group/u/RElbertsen)\
**Post date:** [February 4, 2021, 9:56am UTC](https://openplanetary.discourse.group/t/s5-age-determination-through-crater-counts-on-lunar-geological-maps/434/3 "2021-02-04T09:56:04Z")

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Thanks, that worked. However, now my ArcGIS crashed and I don’t seem to be able to do it again. Nothing happens when I click to set the polygon boundary of the area.

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**Author:** ![Claudia](https://avatars.discourse-cdn.com/v4/letter/c/a88e57/32.png) [@Claudia](https://openplanetary.discourse.group/u/Claudia)\
**Post date:** [February 4, 2021, 10:51am UTC](https://openplanetary.discourse.group/t/s5-age-determination-through-crater-counts-on-lunar-geological-maps/434/4 "2021-02-04T10:51:46Z")

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you can also select a polygon by selecting it from the attribute table if clicking on it does not work

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**Author:** ![lonnekeroelofs](https://avatars.discourse-cdn.com/v4/letter/l/da6949/32.png) [@lonnekeroelofs](https://openplanetary.discourse.group/u/lonnekeroelofs)\
**Post date:** [February 4, 2021, 1:26pm UTC](https://openplanetary.discourse.group/t/s5-age-determination-through-crater-counts-on-lunar-geological-maps/434/5 "2021-02-04T13:26:16Z")

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Hi all,  
I am still trying to fix an error I get in ArcGIS when I am exporting my craters. If I selected the right layers and click export the following error pops up:  
error: Unable to cast COM object of type ‘System.\_\_ComObject’ to interface type ‘ESRI.ArcGIS.Geomotry.IProjectedCoordinateSystem4GEN’. This operation failed because QueryInterface call on the COM component for the interface with IID ‘{D44EDB15-8866-4641-872D-3C81F73AC8AA}’ failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E\_NOINTERFACE)).  
I really don’t know what is happening here and I hope someone can help me!  
Cheers,  
Lonneke

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**Author:** ![lonnekeroelofs](https://avatars.discourse-cdn.com/v4/letter/l/da6949/32.png) [@lonnekeroelofs](https://openplanetary.discourse.group/u/lonnekeroelofs)\
**Post date:** [February 4, 2021, 1:35pm UTC](https://openplanetary.discourse.group/t/s5-age-determination-through-crater-counts-on-lunar-geological-maps/434/6 "2021-02-04T13:35:50Z")

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I have figured out that it probably has to do with the fact that my crater layer does not have a coordinate system. I have know idea how that happened, but I cannot find the right way to change it.