Questions tagged [geography]
Questions using this tag are likely to be off-topic because this is the Geographic Information Systems (GIS) Stack Exchange and its scope does not stretch to general geography
71
questions
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ST_COVEREDBY passes using geometry but fails with geography
I have a table of points and a table of polygons in PostgreSQL 11.18 and PostGIS 2.4.4. Both use Geography SRS 4326.
CREATE TABLE my_points (
id integer generated by default as identity,
geom ...
- 665
1
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1
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53
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Can I use WGS 84 and geometry calculations to check if a point is inside a polygon?
I'm storing polygons in a PostGIS database. The shape of the polygons is stored in a field of type geometry(Polygon,4326).
From time to time, I need to check if a point (of type geometry(Point,4326)) ...
- 143
0
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0
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30
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Determine whether two circles drawn around two lat/long points with two radii intersect
I am trying to find a way to check whether two circles drawn around two lat/long points intersect.
For example,
x1 = (lat1 in degree, long1 in degree)
x2 = (lat2 in degree, long2 in degree)
c1 = ...
0
votes
1
answer
100
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ST_Boundary for geography polygon
I'm trying to calculate the intersection point between a segment and the exterior ring of a polygon. But I'm not sure how to do it correctly when dealing with geography types.
The segment is a line ...
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0
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51
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Identify the coordinate system of an asbuilt
I got an asbuilt with coordinates of (N 4,118,589 and E 4,271,673). It's located in Los Angeles County but I have no idea what coordinate system it is. Anyone got any idea? I thought it would be state ...
0
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0
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116
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MSSQL : Find polygons with in a distance of a point
I am trying to find all polygons (both polygons and multipolygons) that are with in a certain distance of a point.
I have a table with both geography polygons and multipolygons. I want to set a point ...
-2
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1
answer
37
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Which state does this area belong to? [closed]
I'm not a native English speaker and I'm learning the US state names and capitals. Which state does green arrow pointed area belong to?
I highlighted it on Google Map.
It's the blue dashed line ...
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1
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1
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109
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Distances between countries based on borders in R?
I am trying to calculate the distances using rnaturalearth.
library(rnaturalearth)
kr = ne_countries(returnclass="sf")
d = st_distance(kr[128,],kr)
but the following error appear:
Error ...
- 113
0
votes
1
answer
74
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Migrating from PostGIS 1.5 to 3.2: need to replace geography_typmod_dims
I can't find a replacement function for geography_typmod_dims which is used in an old application.
In 1.5 there were:
geography_typmod_dims, _in, _out, _srid and _type.
In 3.2 I find only:
...
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0
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0
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77
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I couldn't find Landsat 5 scene starting from 2002-08-04 to 2008-06-01
I am searching for Landsat 5 TM image from 2000 to 2012 in Earth Explorer Web site (https://earthexplorer.usgs.gov/). However, I couldn't find any scene in my study area starting from 2002-08-04 to ...
1
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0
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44
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What CRS is my data being transformed to in ST_Project? What about ::geometry?
My understanding is that ::geography transforms data from whatever CRS into 4326. But what is ::geometry doing?
Relatedly, in the context of the ST_Project function:
st_project(a.geom::geography,b....
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0
votes
0
answers
65
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Different results for GEOGRAPHY and ST_TRANSFORM query on geo_point field
I am finding properties that are within 20K distance using ST_DWithin. But when I try
with ::GEOGRAPHY casting the result is different from ST_Transform. Note: SRID of geo_point field is 4326
Indexed ...
4
votes
0
answers
688
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QGIS Convert Shapefile to MSSQL as geography type
I am using QGIS 3.16 and SQL Server 2019.
I have a shapefile loaded into the project. I have been able to successfully convert the Shapefile to a spatial dataset in SQL Server. My method for doing ...
0
votes
1
answer
257
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Dissolve shapefile polygons on SQL Management Studio 18
This is the first time I am trying to work with a shapefile on SQL and I am a little lost.
I uploaded a shapefile with all the counties of the US and what I am trying to do is to dissolve all ...
0
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1
answer
3k
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ST_GEOGFROMTEXT Multipolygons converted to Polygons BigQuery
My table contains multipolygons in column called BoundaryWKT, which is in a string format. I used function ST_GEOGFROMTEXT(BoundaryWKT) to convert column of multipolygons from string format to a ...
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2
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1
answer
172
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GPS coordinates coming from vehicle connect to streets coordinates
I have two tables:
"Vehicle" includes GPS coordinates from the moving vehicles and has around 3.000.000 rows
"streetCoordinates" includes GPS coordinates of the streets, where the ...
- 205
1
vote
1
answer
708
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Increasing Contrast of Topographic Image in R
Brand new to R, so a little foreign to me, but I Created a topographic image using Landsat, and .hgt data. I got an image out but tried to increase contrast using the scales tool. It is still giving ...
1
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0
answers
2k
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Rendering 3D map in pgAdmin 4 to view Data? [closed]
I found this error 3D geometrics not rendered in view data (pgAdmin 4).
In GeoDjango I've updated my PointField model with dim=3. After successful migration, I cannot see my data in map.
My Django ...
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-4
votes
2
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332
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Straight line through the earth (not core) from America to which country? [closed]
If you were to draw a straight line, or dig a tunnel, through America, where would you end up?
To clarify:
Let's say you have a globe that sits upright on a table so that the south pole is on the ...
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0
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0
answers
110
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Dealing with non-nested geographic units using the RQGIS and tigris R packages
I recently came across this tutorial suggesting that the RQGIS and tigris R packages could be used to overcome issues with non-nested geographies:
https://rpubs.com/corey_sparks/256942
I'm trying to ...
Riley
2
votes
1
answer
450
views
Area between two longitudes? [closed]
I am trying to compute the area between two longitudes (using the angle between them) but am having a hard time. I can do that more easily between latitudes but longitude reveals to be tricky.
Anyone ...
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2
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0
answers
1k
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Use Natural Earth data set in Cesium
I have saved NaturalEarth data set in my desktop. Then I created a view as below.
<script>
var viewer = new Cesium.Viewer('cesiumContainer', {
...
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3
votes
2
answers
5k
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Using SqlGeometry.MakeValid to get a counter-clockwise polygon in SQL Server
The data I've loaded from a shapefile into a geometry column in SQL Server (using NetTopologySuite) is not producing valid GeoJSON when I export it because it doesn't follow the right-hand rule.
I ...
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6
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0
answers
3k
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When does WKT orientation matter for polygon and multipolygon in geography spatial (left/right hand rule, counter-clockwise, clockwise)
I've decide to use sql server on Azure for my gis database.
I'll be dealing with spatial Geography not Geometry.
While inserting some country boundaries using the spatial data in SQL Server, some ...
- 221
0
votes
1
answer
140
views
Kriging: Large standard error very close to known value points
I am attempting to create surfaces of strata via Kriging in Arc GIS from borehole data. In addition to the predicted surface I also want surfaces showing 95% confidence above and below the predicted ...
3
votes
1
answer
222
views
Number of Eastern Africa countries [closed]
Are Rwanda and Burundi part of "Eastern Africa countries" or "East African countries". Some sources are differing.
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0
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1
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111
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Alternative ST_NumGeometries in type geography
In PostGIS (2.1.8) I use function ST_NumGeometries for nums of count geometry. This function have one argument 'geometry' type.
I need this function for geography type. I looked for but I didn't find ...
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0
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1
answer
98
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Malaria Mortality Rate GIS Data [closed]
Can anyone direct me to GIS data for malaria mortality rate?
I am looking for countries in South Asia, but not looking for country level numbers but smaller level numbers like district level.
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1
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1
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3k
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Calculate vertices' coordinates of a rectangle, given midline and broadth of rectangle
I have latitude and longitude of two points making the midline of a rectangle. Now I want to determine coordinates of 4 vertices of that rectangle. I know how to calculate on plane geometry by using ...
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3
answers
7k
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Which is the most accurate method of measuring distance?
I aim to analyse the accuracy of the various methods of geodesic calculations (distance between two points on Earth)based on the three assumed models of Earth - flat, spherical & ellipsoidal.
I ...
2
votes
1
answer
62
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Half of Earth with most landmass [closed]
About 71% of the Earth's surface is covered with water and the remaining 29% is landmass*. If you could theoretically cut the planet in half, with the objective of producing a half with the most ...
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2
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0
answers
54
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CartoDB geom (coordinates) join: without exact match
Trying to join two datasets (layers) on CartoDB based on their geographical fields (in CartoDB's the_geom created field). However, the basic ST_Intersection function does not work since its tolerance ...
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1
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577
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PostGIS - st_intersects using polygons that cross antimeridan/equator
New to using PostGIS and have two situations that I'm working with.
In the one case, I have a polygon that crossed the antemeridian and was detecting whether a two separate points located within that ...
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0
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1
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317
views
Use QuadTree for better complexity on search features
I want to improve the complexity of search specific feature when using this function :
map.forEachFeatureAtPixel(e.pixel, function (feature, layer) {
// Do something..
});
The improvment ...
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1
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1
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198
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"polygon" on sphere postgis geography
I have a set of points defined by their longitude and latitude, and I would like to check if they lie within a "polygon" on sphere. By polygon on sphere, I mean area in between 4 lines going between 4 ...
4
votes
2
answers
1k
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GeoJson to Spatial Geography in sql server 2012, fix orientation of polygon
I've download from Mapzen many geoJson files related to countries with their respective administration level. Then I've parsed all the geoJson files and saved them to my sql server 2012 as geography ...
- 221
0
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1
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76
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Territories that are not connected
I am looking for territories that are divided between two or more countries in a non-contiguous way. E.g, country A receives the western part of the territory, then country B receives a part to its ...
1
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0
answers
79
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Quantifying amount of sunlight falling in a region
I am trying to objectively quantify or provide some form of indication that could point toward the amount of sunlight
Anyone knows if there are any datasets (either instrumental or remotely sensed ...
- 446
6
votes
2
answers
1k
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Is there any online viewer which displays the polygons assuming great circle lines for the edges?
My question is similar to this one: Are there any online WKT editors? The links given in answers have been very useful to me.
However, it seems that when the tools in question display maps, they ...
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1
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73
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Location based service with normal image
We have an image for a park which has been rendered like this:
Now we want to add some geographic service based on the data: building an Android Application with the following features:
Display the ...
- 953
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1
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166
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ArcPad custom edit form validation behaviour
I have a custom ArcPad form, which includes the geography tab. Users use this tab to update coordinates using the GPS. When user press OK in the edit form, I want to first check that they have not ...
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2
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6k
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Order sql server spatial geometry distance by the nearest
I have a geometry column in a table, I want to get the N nearest neighbours; here is a specific example with the geography type
DECLARE @PTO Geography = Geography::STPointFromText('POINT(-57.432546 -...
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0
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228
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Needing to find parent zip code of a bunch of missing zip codes in the US [closed]
We're using MapPoint to export zip code / territory combinations. Unfortunately, the export doesn't include PO Box zip codes which mean that we're missing a lot of zip codes
The PO Box zip codes are ...
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3
votes
1
answer
165
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GIS through Games: Ideas or Links [closed]
I'm managing a project - http://nepanode.anl.gov aimed at improving data awareness and sharing around Environmental impact analysis. I'm struggling to come up with ways to engage users and show them ...
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2
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2
answers
24k
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Equations to convert from global cartesian coordinates to geographic coordinates
First, I needed to convert geographic coordinates (like those received from GPS) to global cartesian coordinates. I found an earlier question (How do I calculate a xyz-position of a gps-position ...
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3
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2
answers
17k
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Geometry datatype to latitude /Longitude MS SQL Server
I need to convert Sql Server geometry datatype to latitude /Longitude
I have just imported a shapefile to my table (geometry)
This query does not work:-
select
geom.Lat as [Latitude],
geom....
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2
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0
answers
48
views
Characterizing territory according to its relief using ArcGIS Desktop?
I want to characterize the territory according to its relief with ArcGis 10. I'm trying to define a wide territory by its relief, but I would like to do it in an automatic or semiautomatic form with ...
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1
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2k
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The ratio Pixel distance to geographical distance?
I have had this problem for several days and I have no idea to solve it.
The problem is that I am trying to find out the length and width of ships from a Bing map. I got the location point (lon, lat)...
2
votes
1
answer
602
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What is the radius of earth [duplicate]
What is the real radius of earth?
Google says 6378.1 km
Wiki says 6371 km
And there are references for 6378.7 km
I'm using maximum radius 6378.7 km in distance calculation in spherical law of ...
- 171
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82
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Postgis add Geography to function()?
i was wondering
im getting different results when using geography() on different positions within a query.
So, whats the most accurate way of forcing geography() over a functions with geometry ...
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