Find a solution to a practical problem probably involving Buffer

[BaranISCEN]

#Buffer 

Hello,

I have a problem and wanted to share it with the community in order to see if anyone was eventually able to help me finding out a solution. I have actually a dataset composed of points and projected on a shapefile describing European countries.

My goal is the following : create a new shapefile, with zones specified 100 kilometers around the boarders in-between all the States, since I want to see if there are more points close to the boarders, or not.

I thought that Buffer would be a nice way to do it but didn't manage to find out how to practically do this. I converted the polygone shapefile once to line, and then used the function Buffer, but there is nothing appearing. I did the same without converting before.

Thank you very much a lot for your help,

[DanPatterson_Retired]

Do a Select by Location and get all the points that are within the polygons (countries)... keep the selection.

Repeat a Select by Location using the points (with the selection) but use the polylines (boundary) and the "within a distance of option" WITH "select from set (aka selection)"

You should now have the points that fall within the countries that are within X units of its boundary.  This would exclude points that don't fall with a country and those that are further from the border than your threshold

[BaranISCEN]

Dear Dan,

Many thanks for your help. Actually, I used "Select by Location" with Select Features from Point with the source layer being by shapefile of european countries. Then I selected the spatial method "are within the source layer".

I created a new layer with the selected points. This time, I used again "Select by Location" with Select Features from "Selected Points" with the source layer being now the Polyline shapefile of european countries. Then I selected the spatial method "are within a distance of the source layer" and put 75 kilometers for the distance, but all the points are always selected.

Do you have any idea ? Thanks a lot

[DanPatterson_Retired]

Was your polyline and your point data in a projected coordinate system?  

No point in querying using planar units when your coordinates are in decimal degrees

[BaranISCEN]

Yes, there are both in GCS_WGS_1984 projected coordinate system

[DanPatterson_Retired]

GCS_WGS_1984  is a Geographic Coordinate System with a WGS1984 datum... that is, it is unprojected and the coordinates are in decimal degrees.

Try to find a projected coordinate system that applies to your study area ie a Lambert Conformal conic, and Albers, anything but Web Mercator

[BaranISCEN]

I see. I used Define Projection to put both the points and countries shapefile in a projected coordinate system (the Lambert Conformal conic one). Unfortunately, nothing change. When I select only the points within the continents and then try to find the points that are within a certain distance to the polyline shapefile of countries with borders (source) it still selects all the points

Sincerely sorry to bother you this much and thanks for all

[DanPatterson_Retired]

You never use Define Projection... unless you get a warning that the file has no defined coordinate system.

You must define it back to what it is. then use the 

Project Tool...

which is the same tool whether you are in ArcMap or ArcGIS Pro

[BaranISCEN]

Thank you so much! It indeed worked. May I ask why the Define Projection was not appropriate ?

Thanks a lot

[NeilAyres]

Because "Define Projection" should only ever be used when you have some data with no defined projection, or when (like in your case), someone mistakenly redefined an existing coordinate system.

Define projection just updates the metadata about the coordinate system of the data but does not actually alter the underlying geometry. To do that you need Project.