topic Re: How do I get my data to show together in New to GIS Questions

How do I get my data to show together

CaroleWacta — Sat, 05 Mar 2016 18:19:23 GMT

I have a point file and boundary file that are all projected to the same projection...

Except that I cannot see them together. each file shows up if I do ZOOM to LAYER, but not on the same screen.

What am I missing? I have attached both files

Thank you.

Re: How do I get my data to show together

JayantaPoddar — Sat, 05 Mar 2016 18:25:25 GMT

If they are meant to overlap, check the extent of both the layers. One of them should be defined a different coordinate system.

Could you mention the extent of both the layers and their projection system?

Re: How do I get my data to show together

CaroleWacta — Sat, 05 Mar 2016 18:29:08 GMT

I will check that...

Where do I find the extend? in the properties?

Thank you

Re: How do I get my data to show together

CaroleWacta — Sat, 05 Mar 2016 18:31:52 GMT

they have different extend...

How do I change that?

Thank yiu

Re: How do I get my data to show together

CaroleWacta — Sat, 05 Mar 2016 18:33:56 GMT

Re: How do I get my data to show together

JayantaPoddar — Sat, 05 Mar 2016 18:37:42 GMT

I don't have an access to any GIS software. If the extent of a shapefile is between 0-180, you need to define a geographic coordinate system (e.g. GCS_WGS_1984)

In ArcCatalog, right-click the shapefile and go to its properties. Edit the spatial reference and define a different coordinate system to check if it falls correctly on Map.

Re: How do I get my data to show together

JayantaPoddar — Sat, 05 Mar 2016 18:42:52 GMT

The traffic data is defined a wrong projection.

From ArcCatalog, go to its properties, and edit the spatial reference to Geographic Coordinate System > World > WGS 1984.

Else you could also define it as GCS_North_American_1983.

Check for the more appropriate coordinate system.

Re: How do I get my data to show together

JayantaPoddar — Sat, 05 Mar 2016 18:53:17 GMT

Since your current projection system is derived from GCS_North_American_1983, I would try this one first.

Re: How do I get my data to show together

CaroleWacta — Sat, 05 Mar 2016 19:02:59 GMT

I see it.

Thank you...

I will try that.

Re: How do I get my data to show together

CaroleWacta — Sat, 05 Mar 2016 19:30:33 GMT

Hello, I can see the second and thirds together, but not the first... Why will this one not show in the window with the two below? they seem to have the same coordinates??

Re: How do I get my data to show together

JayantaPoddar — Sat, 05 Mar 2016 20:07:07 GMT

The coordinate system of "TrafficAccidents" shapefile is still not correct. DO NOT use a Projected Coordinate System for this.

Use Geographic Coordinate System.

Open ArcCatalog.

Navigate to the folder containing "TrafficAccidents" shapefile.

Right-click the shapefile > Properties.

In properties dialog, navigate to Spatial Reference > Edit.

Type "GCS_North_American_1983" in search box. Among the filtered coordinate systems, choose GCS_North_American_1983 under Geographic Coordinate System.

Re: How do I get my data to show together

CaroleWacta — Sat, 05 Mar 2016 20:11:02 GMT

Thank you.

I will do that.

In short, can you please tell me why we should not project? I would like to understand for future reference.

Thank you

Re: How do I get my data to show together

JayantaPoddar — Sat, 05 Mar 2016 20:20:19 GMT

In Projection Coordinate System, the units are linear (feet/meters) like in a 2D Map.

In Geographic Coordinate System the units are angular (Decimal Degrees/ Radians) like in a 3D Globe. Looking at the extent of TrafficAccidents shapefile, we can say that the extent is too small to be in linear units. They have to be in angular units like Decimal Degrees. So we are choosing a GCS for defining its coordinate system.

Once defined, you can reproject it using Project—Data Management toolbox | ArcGIS for Desktop .

Also check the following link.

Projection basics for GIS professionals—Help | ArcGIS for Desktop

Re: How do I get my data to show together

CaroleWacta — Sat, 05 Mar 2016 20:39:35 GMT

Thank you.. It worked... Tks a lot