topic Re: Georeferencing Google Earth Screenshots in Data Management Questions

Georeferencing Google Earth Screenshots

HazelAng1 — Thu, 26 Mar 2015 13:42:57 GMT

Hi all, I have recently georeferenced some screenshots from google earth by using Inputs X and Y and keyed in the lat long. However, I realised that the values I have keyed in have units as meters and not degrees. As such, I am having trouble now while trying to digitise some parcels because the combined raster image is too small for digitisation to be done.

How can I convert the units for the X and Y that I have keyed in from meters into degrees? Sadly, I accidentally deleted the individual georeferenced images after I have merged them into one using mosaic.

Re: Georeferencing Google Earth Screenshots

StevenGraf1 — Thu, 26 Mar 2015 14:11:38 GMT

If you know the UTM Zone you are working in, here is a UTM to Decimal Degrees Converter.

Geographic/UTM Coordinate Converter

Steven

Re: Georeferencing Google Earth Screenshots

JayantaPoddar — Thu, 26 Mar 2015 14:22:29 GMT

Hi Hazel,

From ArcCatalog, right-click the image that you had georeferenced > Properties. Scroll down to spatial reference > Click Edit.

In Spatial Reference properties dialog box, go to Geographic Coordinate System > World > WGS 1984. Select it. Click OK > Click OK.

Open the image in a new ArcMap session. Hope it resolves the issue.

Thanks,

Jay

Re: Georeferencing Google Earth Screenshots

AnthonyGiles — Thu, 26 Mar 2015 14:29:29 GMT

Hazel,

There is no way that you can, there is no relation to entering 64 meters instead of 64 degrees for example. You will need to drop all projection information from your mosaic and re-georeference it.

Regards

Anthony

Re: Georeferencing Google Earth Screenshots

HazelAng1 — Thu, 26 Mar 2015 14:32:52 GMT

Hi Jay

I have just tried your method but my raster layer has already been set at PCS WGS1984. Hence the issue is still persisting.

Re: Georeferencing Google Earth Screenshots

HazelAng1 — Thu, 26 Mar 2015 14:34:30 GMT

Hi Anthony

Seems like I may have to regeoreference them. However, am I able to do so from the raster layer which is merged? Because the merged raster layer does not have any georeferenced information. Only the original raster images have them.

Re: Georeferencing Google Earth Screenshots

JayantaPoddar — Thu, 26 Mar 2015 15:13:58 GMT

It should be GCS WGS 1984, not PCS. And you don't have to georeference it again

Re: Georeferencing Google Earth Screenshots

JayantaPoddar — Thu, 26 Mar 2015 15:21:03 GMT

Here is the snapshot for you

Re: Georeferencing Google Earth Screenshots

AlicePence — Thu, 26 Mar 2015 16:24:37 GMT

Have you tried using Field Calculator? There's an option to convert from meters to degrees ArcGIS Help (10.2, 10.2.1, and 10.2.2)

Re: Georeferencing Google Earth Screenshots

SheldonBaker — Thu, 26 Mar 2015 17:06:17 GMT

I am sure this is not the answer you are looking for. But read carefully your Google Earth terms of service. I believe they may prohibit this. They make it difficult on purpose. So I have heard. But you can probably get just as good imagery from ESRI.

Re: Georeferencing Google Earth Screenshots

HazelAng1 — Fri, 27 Mar 2015 15:22:45 GMT

Hi Jay, thanks a lot for your advice. I will try it again tomorrow. Hopefully it will work.

Re: Georeferencing Google Earth Screenshots

LianVon_Wielligh1 — Sat, 28 Mar 2015 15:48:49 GMT

I'm not sure I understand your question, hope this is helps. Why don't you export your map as a jpeg and then import it again for georeferencing using baseman of your preference. I do a similar thing using aerial photography of forests for vegetation mapping.

ArcGIS Help 10.1

Try this link.