Scripting (Python) Feature Class content into Shapefiles based on an UTM data structure

[EduardoAbreu-Freire]

Consider a Feature Class (part of an Enterprise GDB content) and two of its fields are "UTM_grid" and the "OID".

Scripting with python 2.7 for ArcGIS 10.3.

"UTM_grid" field was broken down into "UTM_block" + "UTM_sheet" and then using a dictionary and list structure UTM_block-->UTM_sheet-->OID was organized with this syntax:

{ 'UTM_block_1' : { 'UTM_sheet_A' : [ oid_1 , oid_2 ] }, { UTM_sheet_2 : [ oid_3 , oid_4, oid_5 ] } }

We need to create **shapefiles** with features (identified by the object value - oid) based on the follow data structure (OIDs will be organized regarding an UTM/location based structure):

- UTM_block_* will be a folder

- UTM-sheet_* its subfolder.

- List of objects (OIDs) will populate the shapefile.

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Another point we have to deal with is that the shapefile should only have some fields of the original Feature Class:

We have used fieldmappings and arcpy.FeatureClassToFeatureClass_conversion() to create a non-UTM-organized shapefile from a Feature Class with the fields that we need.

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Now the problem is how to process the **feature export** to get UTM-organized shapefiles! How can we manage it?

Bellow is what we have now inside a function:

    with arcpy.da.SearchCursor(feature_class, ['UTM_grid , 'OBJECTID']) as cursor:
        dic = dict()
        for row in cursor:
            UTM_grid_value = row[0]
            oid_value = row[1]

            try:
                b_s_split = UTM_grid_value.split('_')     # split into block & sheet

            except Exception, e:
                pass
                print(UTM_grid_value)
                print(e)

            else:
                # create folders & subfolders (blocks & sheets) in a directory
                dic.setdefault( b_s_split[0], {} ).setdefault( b_s_split[1], [] ).append( oid_value )
                dir_path = os.path.dirname("E:\\")     # full path to directory
                dirs = [ [b_s_split[0]] , [b_s_split[1]] ]
              
                for item in itertools.product(*dirs):
                    if not os.path.isdir(os.path.join(dir_path, *item)):
                        os.makedirs(os.path.join(dir_path, *item))

[DanPatterson_Retired]

I must be missing where the features to export is coming from assuming that creates the necessary folder structure

[EduardoAbreu-Freire]

Hi Dan Patterson Blake Terhune​​

Features classes to export are in a SDE geodatabase. We read/list the FCs in that GDB and for each FC we need to process the export of its features by UTM block-sheet into shapefiles.

The FC includes a field which identifies the location (as shown in code).

e.g. B1SD40B --> breaking down into "block" + "sheet" results in "B1" + "SD40B".

Looking at the fields "UTM_grid" and "ObjectID" we check while sheet ( utm_grid[1] ) = "SD40B", read the corresponding OID, and put the Feature into a Shapefile inside the directory (which has the associated sheet name). The same logic could be used to organize sheets inside the block directories.

[BlakeTerhune]

I think Dan Patterson is asking how you find the feature class to export? In other words, how do we know where to go to export the OIDs for each sheet. Is there something in the UTM grid data that identifies the feature class to export?

[EduardoAbreu-Freire]

My comment was edited to clarify that point, thank you.

[BlakeTerhune]

So you're iterating a list of feature classes, opening the search cursor on each one, and exporting certain ObjectIDs in the whole feature class based on the ObjectIDs listed in the UTM_Grid field of each record? Seems like that would be ripe for duplicates. Could you upload some sample data?

[EduardoAbreu-Freire]

Blake Terhune yes, we want to export certain OIDs from the whole FC, but that selection is based on the "childs" derived from the "parent" UTM_grid. Childs mean block and its sheets.

Am sending you a simplified FC (polygon) we are using for test which already has the attributes we need.

FOL_250K is a short name for FOLHA (meaning sheet) and 250K (is the scale). I posted the question replacing FOL_250K by UTM_grid. So consider the real name as you need.

https://www.dropbox.com/s/7z6m4rgij3lxlyu/gdb2shp_selected_fields.gdb.zip?dl=0

[BlakeTerhune]

Sorry, I still don't quite follow. I don't see a UTM_grid field in the data you uploaded, nor do I see any lists of OIDs. Do you have some other Python function that dissolves the FOL_250K field into OIDs?

It looks like there are four distinct values in FOL_250K:

BLOCO1 - SULD33S - Namibe

BLOCO1 - SULD33T - Chibia

BLOCO1 - SULE33B - Oncócua

BLOCO3 - SULC33U

Should it make output folders and shapefiles like this?

BLOCO1

.. SULD33S

.... Namibe.shp

.. SULD33T

.... Chibia.shp

.. SULD33B

.... Oncócua.shp

BLOCO3

.. SULC33U

.... None.shp

[EduardoAbreu-Freire]

Blake Terhune​

When I posted the problem I wrote "UTM_grid" to give it a more readable name 😃

The file/FC contains the real names. FOL_250K is UTM_grid.

FOL_250K shows those labels (e.g.     BLOCO1 - SULD33T - Chibia)

but the value is B1_SULD33T.  We do not need to dissolve FOL_250K.

with arcpy.da.SearchCursor(gab_und_crt_dic, ['FOL_250K' , 'OBJECTID']) as cursor:       
        for row in cursor:
            fol_250k_value = row[0]
            oid_value = row[1]

fol_250k_value returns a value in the format (B1_SULD33T).

Output structure we need:

B1

.. SULD33S

.... B1_SULD33S_<featureClassName>.shp

.. SULD33T

.... B1_SULD33T_<featureClassName>.shp

B3

.. SULC33U

.... B3_SULC33U_<featureClassName>.shp

(in this case <featureClassName> will be gab_und_crt_dic)

[BlakeTerhune]

So the value in the FOL_250K field of the sample data you uploaded is not correct? It's hard to parse a value when you don't know what the value is supposed to look like.

Are you saying instead of the value being BLOCO1 - SULD33T - Chibia, it should be B1SULD33T? How do you parse that into block and sheet? At the first S?