topic Re: create a layer using python in ArcMap 10.4 in Python Questions

create a layer using python in ArcMap 10.4

PaulHacker2 — Wed, 15 Jun 2016 15:48:30 GMT

I'm a self taught (well still learning) Python/ArcGis programmer. The company I work for does well maps.

How does one use python to create a layer?

I know I can click down to the personal Geodatabase.mdb on ArcMaps and right click and do a 'create layer' but we have a huge number of maps to create and we have a large library of GDB to make into layers on maps. I would hope the script behind that 'create layer' would be visible but it isn't.

I want to make a batch process to do all the work instead of getting on ArcMap 10.4 and doing them one by one. I presume arcpy and one (or several of the functions/methods) are used.

Thanks for any help!

Re: create a layer using python in ArcMap 10.4

WesMiller — Wed, 15 Jun 2016 15:53:42 GMT

For a layer

Make Feature Layer—Help | ArcGIS for Desktop

For a feature class

Create Feature Class—Help | ArcGIS for Desktop

Re: create a layer using python in ArcMap 10.4

PaulHacker2 — Wed, 15 Jun 2016 16:13:29 GMT

Thanks but the create feature class has linkrot. At least it cannot find it. How did you find it?

Paul

Re: create a layer using python in ArcMap 10.4

WesMiller — Wed, 15 Jun 2016 16:17:55 GMT

Try copy and paste

"http://desktop.arcgis.com/en/arcmap/latest/tools/data-management-toolbox/create-feature-class.htm"

Re: create a layer using python in ArcMap 10.4

PaulHacker2 — Wed, 15 Jun 2016 17:50:37 GMT

got it. Thanks!

Re: create a layer using python in ArcMap 10.4

PaulHacker2 — Fri, 17 Jun 2016 15:32:33 GMT

Question.. which comes first. the layer or the feature class?

Thanks.

Re: create a layer using python in ArcMap 10.4

DarrenWiens2 — Fri, 17 Jun 2016 15:51:13 GMT

Serious question or classic joke?

Re: create a layer using python in ArcMap 10.4

PaulHacker2 — Fri, 17 Jun 2016 16:13:21 GMT

No. I now see I first run the CreateFeatureclass_management and then MakeFeatureLayer. But it is going to be complicated as I have to find out where the spatial_reference template they want me to use!

Sadly they are on vacation.... Thanks anyway.

Re: create a layer using python in ArcMap 10.4

MicahBabinski — Sat, 11 Dec 2021 09:30:48 GMT

Heya Paul,

Congratulations on diving into Python! Yours is a classic example of why folks should learn Python and arcpy.

You may wish to also check out the Save to Layer File GP tool. You could implement it like:

import os, arcpy
arcpy.env.workspace = r'C:\gisdata\mdb\roads.mdb'
layerFileFolder = r'C:\gisdata\layerFiles'
for fc in arcpy.ListFeatureClasses():
    arcpy.MakeFeatureLayer_management(fc, 'tempLayer')
    arcpy.SaveToLayerFile_management('tempLayer', os.path.join(layerFileFolder, arcpy.Describe(fc).baseName + '.lyr'))

Hope this helps! Happy scripting.

Micah

Re: create a layer using python in ArcMap 10.4

PaulHacker2 — Fri, 17 Jun 2016 20:42:31 GMT

Thanks guys, here is where I'm at.

In a created GDB we have four classes already there (in hundreds of these.)

MAPGRID_003_076.gdb

MapGrid

A_003_076 - Geodatabase Feature Class

B_003_076 - Geodatabase Feature Class

C_003_076 - Geodatabase Feature Class

D_003_076 - Geodatabase Feature Class

And in a template GDB they have the same Classes but three more they want to copy.

But these three Feature Classes have some data.

CountyCode_MapGrid-template.gdb

MapGrid

F_mapgrid_number <--want to copy this Geodatabase Feature Class

A_mapgrid_number

G_mapgrid_number <--want to copy this Geodatabase Feature Class

B_mapgrid_number

H_mapgrid_number <--want to copy this Geodatabase Feature Class

C_mapgrid_number

D_mapgrid_number

So F, G, and H have to be copied AND renamed so the 'mapgrid_number' = such as '003_076'.

I created them using...

arcpy.CreateFeatureclass_management(out_path, out_name, geometry_type, template, has_m, has_z, spatial_reference)

Which works fine and ArcMap shows it up.

But now I need to copy INTO the new created F, G, and H Geodatabase Feature Class from another GDB that already has a F, G, and H Geodatabase Feature Classes that has data they want to show up on ALL of them.

Now do I create as I did above and then use arcpy.CopyFeatures_management to overlay the new F, G, and H I already have or is there some way to skip the create and just copy it across.

Thanks,

Paul

Re: create a layer using python in ArcMap 10.4

MicahBabinski — Fri, 17 Jun 2016 21:16:32 GMT

Hi Paul,

If I understand what you are trying to do, then I think Append (management) and Rename (management) will get you there. However...

Paul Hacker wrote:
But now I need to copy INTO the new created F, G, and H Geodatabase Feature Class from another GDB that already has a F, G, and H Geodatabase Feature Classes that has data they want to show up on ALL of them.

...why not just copy the feature classes over, rather than creating a new (empty) feature class and loading data into it? That way you would get it done in fewer steps.

Micah

Re: create a layer using python in ArcMap 10.4

WesMiller — Sat, 18 Jun 2016 12:26:52 GMT

Have a look at Feature Class To Feature Class—Help | ArcGIS for Desktop tool

Re: create a layer using python in ArcMap 10.4

PaulHacker2 — Mon, 20 Jun 2016 16:15:14 GMT

Thanks guys.

I got the first part to work perfect (creating features for all 189 of 'em!) using arcpy.CreateFeatureclass_management.

Now on FeatureClassToFeatureClass_conversion (copying a template to the newly created feature classes.)

My ArcMap shows the template I wish to copy/convert as:

c:\output

- maps

- code_mapgrid.mdb

- Mapgrid

[] Block_template_number (feature class I wan to copy but rename with such as Block_002_003)

Does the arcpy.env.workspace point to the mdb where the class is? How does it know where to find the inFeatures?

arcpy.FeatureClassToFeatureClass_conversion(inFeatures, outLocation, outFeatureClass, expression)

All want it to do is copy over the blank features (Block_002_003) I made in the new GDB with features in the template mdb (Block_template_number).

Thanks,

Paul

Re: create a layer using python in ArcMap 10.4

WesMiller — Mon, 20 Jun 2016 16:35:55 GMT

If you just want the schema and not any records. You could use create feature class and use the existing feature classes as a template. See creating feature class above

Re: create a layer using python in ArcMap 10.4

PaulHacker2 — Mon, 20 Jun 2016 17:59:58 GMT

Thanks. We need the records that are in them.

Paul

Re: create a layer using python in ArcMap 10.4

MicahBabinski — Mon, 20 Jun 2016 21:54:13 GMT

So you have created empty feature classes in your personal geodatabase, and now want to load some features into them? For that, you would use Append (management). Feature Class To Feature Class will write an entire feature class to a given output location. It's just a little unclear what exactly you are going for.

Here's a tip: before writing any code, start by writing a step-by-step explanation of what you want your script to do, in the simplest possible terms. I do that regularly and it helps me complete the script, and ask for help if I need it. Then, if you complete your process using individual geoprocessing tools, you can go to your results tab (Geoprocessing Menu -> Results), right-click a tool, and select 'Copy as Python snippet.' Then you can paste that into a script to see how the parameters work. Also, if you have ModelBuilder experience you can set up your process in ModelBuilder and then choose Export -> Export to Python Script. This may also help you understand how parameters and results of tools are handled (although the script often comes out a little hard to understand).

Re: create a layer using python in ArcMap 10.4

PaulHacker2 — Tue, 21 Jun 2016 13:22:31 GMT

Thanks. I would have made the sniplet if the license they got for my ArcMap allowed it. And it would have made my life MUCH simpler.

I'll now research the Append and get it to work.

Thanks.