8

Here's an attempt with postgis. i've used data imported from natural earth data, admin level 1, 1:10m scale. This will take a long time as it's a 4-way cartesian join with st_relate(). The magic number "FF2F11212" should match when two polygons' intersections are a line, but not when they join at a point. This uses something called DE-9IM. I use a ...


6

I dont think there is a way of only symbolizing the outer borders. But you can use Dissolve tool to create a new feature class which will not have the inner borders. Then select no fill/transparent fill and symbolize only the borders. (You probably dont need to use any dissolve attribute)


5

QGIS or. GDAL NEARBLACK is what you are looking for http://www.gdal.org/nearblack.html Convert nearly black/white borders to black. nearblack [-of format] [-white | [-color c1,c2,c3...cn]*] [-near dist] [-nb non_black_pixels]


4

Topology tools may not be necessary in your case. I would transfer the Wards attribute (feature to points, then spatial join) to the census polygon, then dissolve based on the Wards unique identifier. This will yield a new feature class with the attributes of Ward and the boundaries of the Census.


4

A simple way would be to have your national borders in a separate file from your subnational borders. Here is an example if you use the most-detailed border datasets from Natural Earth Data (http://www.naturalearthdata.com/downloads/10m-cultural-vectors/). I downloaded both the "Admin 0 - Countries" and "Admin 1- States/Provinces" datasets. They should ...


3

A web search turned up this download site for world maritime boundaries as an ESRI shapefile. Here are directions for converting the shapefile to geojson using QGIS and here for ArcMap.


3

Start Editing Select two districts you want to merge into one, and from the Editor toolbar menu select "Merge" A dialog will appear for you to select which record to copy attributes from - select the one you want to keep attributes and click OK Your selected polygons will now be merged. Repeat for the other districts you would like to merge.


3

Create a copy of your features, apply following field calculator expression on field Shape, using Python parser: def outRing(shp): part=shp.getPart(0) pgon=arcpy.Polygon(part) return pgon ------------------------ outRing( !Shape!) When working on shapefile, no need to switch editing on.


3

County and Parish are no longer part of legal descriptions of land. The do still feature on survey plans and property contracts, but more so for historical reference purposes. Parish boundaries were drawn on Parish Maps which were fairly small scale and paid little (if any) attention to features outside the boundary. Here's a sample. You can find others ...


3

Looking at the code and at this algorithm description (not the PostGIS one), it appears that the amount of input point does matter. The algorithm needs to look at nearby points to find the concave hull. In your example, the input vertices "inside" the main polygon are closer to the boundary on the other side of the polygon than from their connected vertices. ...


3

If you're familiar with the command line: Download boundaries as JSON (not GeoJSON!) file directly from Overpass API into a local file, via Export --> raw data directly from Overpass API in overpass turbo. Convert the JSON file via a nodejs script from JSON into GeoJSON. In case you want to use the same library that is in place for overpass turbo, you ...


3

There are a bunch of tools that can help with this. Check out this article for more details: http://desktop.arcgis.com/en/arcmap/10.4/manage-data/editing-fundamentals/removing-slivers-or-gaps-between-polygons.htm More specifically the Align to Shape tool will hopefully solve your problem: http://desktop.arcgis.com/en/arcmap/10.4/manage-data/editing-existing-...


3

First, you need two datasets: US zip code areas - the actual zip code areas are only available as a very expensive subscription service from the US Postal Service. However, you can probably make do with the zip code tabulation areas (ZCTAs) from the Census Bureau. ZCTAs are updated every ten years; the current ZCTAs are from 2010 (after the 2020 census data ...


2

After taking @PolyGo's suggestion, I contacted QSpatial regarding if a parish boundary dataset exists for Queensland (Australia) - this was the response: "Parish names and boundaries are actually historical information. Parish mapping and the parish information in the DCDB has not been maintained for many years. Unfortunately as the parish boundaries are ...


2

You should be able to get this from the Queensland Spatial Catalogue (QSpatial). The Cadastral (DCDB) datasets, at least for each Local Government Area (LGA), have a field for PARISH, which can be used to dissolve them out. The only catch is that there will be gaps in the dissolved parishes that represent the roads. I think that it is quite likely that ...


2

Since a raster is always a matrix of individual pixels, there's no way to get rid of the zig-zag along the edges, when you clip on an angle. However, if you can increase the resolution of the raster (interpolation to a higher resolution) then the gaps will be small enough that it should not be a problem.


2

The Natural Earth 10m Cultural dataset has a polygon layer of territorial disputes, which includes Bhutan.


2

Use a negative buffer to offset the boundaries of the polygons. This will create a slight gap between each polygon allowing for the outline boundary not to overlap. Experiment with the negative number until you are satisfied. Set the Input, Output and (minus) Linear Unit, the rest of the fields can be left as default.The attribute values will remain in-tact ...


2

By the geography advanced FAQ http://postgis.net/docs/using_postgis_dbmanagement.html#idm1391 what you experience is intentional What is the longest arc you can process? We use great circle arcs as the "interpolation line" between two points. That means any two points are actually joined up two ways, depending on which direction you travel ...


2

Turns out this information is readily available, but it is buried a little bit in the census's website. If this link is followed: https://www.census.gov/rdo/data/113th_congressional_and_2012_state_legislative_district_plans.html the data can be found. It is easy to miss, but can be found under the heading '113th Congress and 2012 State Legislative Block ...


2

ST_Relate can do that; you can specifically define the spatial relation you want by using the DE-9IM.A query would look like this: SELECT a.* FROM a JOIN b ON ST_Intersects(a.geom, b.geom) WHERE ST_Relate(a.geom, b.geom, 'TT*FT*FF*') I made the matrix out of my head...you might need to alter it accordingly. Check out this blog.


2

Lund University has a nice website with a list of sites with everything from static map, GIS data, images to fully interactive map services. https://www.gis.lu.se/geographical-data/geographical-data-for-everyone They also have a specifc agreement with swedish agencies to provide data to their students and staff. Not sure if it is your case but here is the ...


2

Here's an example using shapely, based on the shapely documentation. https://toblerity.org/shapely/manual.html#binary-predicates from shapely import geometry polygon = [(3, 2), (5, 1), (7, 2), (8, 6), (9, 7), (11, 6), (10, 4), (12, 2), (15, 2), (16, 5), (19, 7), (18, 11), (14, 12), (11, 9), (5, 9), (2, 6)] Point_X = 14 Point_Y = 12 line = geometry....


2

You can create a border around the classes via a virtual layer. The virtual layer would create the polygon union by class, and you then style it to show just the border. Note that it works best on smaller datasets. So, go to the menu layer / add layer / add/edit virtual layer and enter the query select st_union(geometry) from myLayer group by myClass ...


2

Vector -> Geometry Tools -> Extract Nodes then Vector -> Geometry Tools -> Add Geometry Column gives you for each corner node of your polgyons and then adds it's coordinates to your attribute table.


2

Yes, a MapInfo table can have bounds that limits the data extent of the table. The benefit of this is to get a better precision of the coordinates. You can check the bounds of your data with the Coordsys Bounds Manager tool that you can find in the Tool Manager. If you want to learn more about the tool and bounds, have a look at this discussion on Li360.


2

This data source (from the Australian Bureau of Agriculture and Resource Economics and Sciences) includes irrigation areas for most of Australia.


2

If you want to get attributes from one polygon set to another (say cenus to taxi - or vice versa) then you would be best doing a Spatial Join. For your use case I'd recommend setting the match_option to HAVE_THEIR_CENTER_IN. This way you don't need to worry about small discrepecies around the edges if the bulk of each polygon is the same. To get a sum, ...


2

If I understand well the question, it should be solved using the Align Edge tool on the Topology toolbar. Check the ESRI documentation page and this youtube video.


2

What do you mean by "The function doesn't work"? It does work for me. SELECT ST_AsText(ST_Boundary(ST_GeomFromText('MULTIPOLYGON ((( 340 520, 400 460, 200 420, 340 520 )), (( 420 420, 520 300, 340 320, 420 420 )))'))); Result: MULTILINESTRING((340 520,400 460,200 420,340 520),(420 420,520 300,340 320,420 420)) The result is a multilinestring with two ...


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