Tuesday, July 21, 2015

Questions about 1986 geographic (DCF) files

Question

What is the difference between

· Agec86cd.e00 and crd86.e00 (agriculture ecumene files)
· Popin86.e00, popline86.e00, and polout86.e00 (population ecumene files)

I have converted these (and all the other 1986 files) to shape file format, but I’m not sure why there are the multiple files, or what they hold. Neither the b01.pdf file nor the inventories explain this.

Answer


Most likely these are a combination of the spatial boundary files that make up the ecumene boundaries.

For example the population ecumene usually consists of 3 separate layers including the ecumene boundary layer, the census divisions boundary layer, and the province boundary layer. However those names don’t really line up.

What do the converted shp files show you? Can you derive from the attribute table what they may cover?

After consulting with subject matter I hope this helps clear up the confusion:

AG
Agec86cd.e00:

This file seems to follow CDs in agricultural areas of Canada. Though in sparser areas the file takes into account the ecumene surrounding specific CSDs.

So in areas like populated southern Ontario and the prairies (the southern halves of Manitoba and Saskatchewan and eastern Alberta) follows the CDs. In sparser areas, a buffer appears to have been created that follows the smaller, more populated areas.

An example of this would be CSD 5939007 where a buffer has been created around it and added to Agec86cd.e00. See the below screenshot (CSD = orange, Agec86cd.e00 = blue)



The data associated with Agec86cd.e00 (note there is no CSD data)

OBJECTID 410
SHAPE Polygon
AREA 650083300
PERIMETER 93379.83
AGEC86_CD2_ 53
AGEC86_CD2_ID 317
CD86 5939
PR_ID 59
CD 39
e00_centroid_x 4509025.5
e00_centroid_y 2022825.6

The field CD86 references the CD around it. Other examples may overlap several CDs (if they are in the less populated areas) and has been given a CD value that it seems to overlap – there are duplicates in this field, obviously.

There is no apparent UID – field AGEC86_CD2_ seems to be it – and it is just sequential numbers.

crd86.e00:

This file is only Alberta and southern regions of Saskatchewan and Alberta. The file seems to group CSDs or CCSs but not CDs. There is no buffering or adjustments made to this file. It does contain data names that may correspond with Agricultural regions (CRDNAME examples include 1A and 3AS (Saskatchewan), and numbers 1 to N (Alberta, Manitoba).

OBJECTID 76
SHAPE Polygon
AREA 26058500000
PERIMETER 734625
CRD86_ 36
CRD86_ID 36
GLABEL CRD4781
TILE SAS8A
TAF S08A
CRDNAME 8A
e00_centroid_x 5464762.5
e00_centroid_y 1933594.3


The two bolded fields have the name mentioned above an a unique ID – the label.

POP
popin86.e00:

Ecumene of populated areas – follows the CD boundaries in densely populated areas but in more northern areas or less densely populated areas it may be a buffer of a CSD (like the Ag file above) OR it may be what appears to be a manually created polygon that takes two CSDs and joins a region in between or on the edge of one where it may be more densely populated. Has a CDUID associated with it:

OBJECTID 435
SHAPE Polygon
AREA 3013117000
PERIMETER 275614.5
POPIN86_ 89
POPIN86_ID 116
CD86 4718
e00_centroid_x 5552235.5
e00_centroid_y 2057639.6
popline86.e00:

The above file but no divisions into CDs (all of the prairies is one polygon; all of the western side of the St. Lawrence/Southern Ontario region is one polygon).

popout86.e00:

The same as popin86 but the inverse. Follows CD boundaries but has no populated regions included. It does contain more northern areas (and non-coastal) that are in popin86. But these can be excluded using the CD88 field where the value is “OUT” – this will also exclude Great Bear and Great Slave lakes.

Here is a screenshot of the three together:
Blue lines: popin
Pink: popout
Grey line: popline




EXPORTING FILES:

If you export to a shapefile from the “umbrella” of the E00 file it will export all the data (including the “empty” files).

If you export only the polygon file with attributes you should be okay and only get the polygon file.