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14 votes

converting/parsing geojson into com.vividsolutions.jts geometry

For a much more lightweight alternative to GeoTools, check out jts2geojson: GeoJSONReader reader = new GeoJSONReader(); Geometry geometry = reader.read(json);
dbaston's user avatar
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8 votes
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Calculate distance with JTS

The short answer is you can't do that unless your points are very close together and you want the answer in degrees. JTS knows nothing about units or the curvature of the earth. So you need to pull in ...
Ian Turton's user avatar
  • 79.9k
7 votes

GeoJSON java library

Another alternative is GeoGson, which is built on top of Google's Gson: Geometry geometry = new GsonBuilder() .registerTypeAdapterFactory(new GeometryAdapterFactory()) .create() ...
simon04's user avatar
  • 177
6 votes

Avoiding GeoServer/Java out of heap space error?

I've had the same error message on a Windows Server with GeoServer using Jetty. After some research I found the file C:\Program Files (x86)\GeoServer 2.10.1\wrapper\wrapper.conf where I edited these ...
Franka's user avatar
  • 161
6 votes
Accepted

Given a GeoJSON file how do I calculate the area of the embedded features?

GeoTools is a Java library which can read and write GeoJSON and provides access to features like area via the JTS library. It will also help you to reproject the geometries from the lat/lon of GeoJSON ...
Ian Turton's user avatar
  • 79.9k
6 votes
Accepted

Convert geojson to png

If you chose GeoTools it is a fairly simple process, fetch your geojson from somewhere: URL states = new URL("http://geojson.xyz/naturalearth-3.3.0/ne_110m_admin_1_states_provinces.geojson"); ...
Ian Turton's user avatar
  • 79.9k
6 votes

Remove/Fill holes in Polygons from a MultiPolygon using JTS Topology Suite programmatically

OpenJUMP has a "remove holes" tool (and an advanced "remove small holes" tool as well). OpenJUMP often uses JTS rather directly but I am not sure about this case. The source code of the function is at ...
user30184's user avatar
  • 62k
5 votes

How can I find closest point on a polygon from a point

A very simple solution: solve an equasion for each pair of poly vertices. An algorithm for one segment of the polygon (gray in the picture) with points a and b: vector A is just point a coordinates ...
culebrón's user avatar
  • 2,314
5 votes

How to calculate the distance between a line and a point (using lat/lon coordinates)

you can't really convert convert distances in degrees into meters as the size of a degree varies as you approach the poles. convert your locations into a projected coordinate system, then calculate ...
Adam's user avatar
  • 1,383
5 votes

Testing if Geometry is convex using JTS?

OK, my original answer was wrong (see user30184's comment). Here's another: The polygon is convex if each interior angle is 180 degrees or less. You can check this in O(n) time, iterating over the ...
Rob Skelly's user avatar
  • 3,101
5 votes
Accepted

Create shapefile based on geojson data with geotools (Java)

Short answer: Your feature type doesn't match the Shapefile standard so the illegal bits get dropped by GeoTools. I have a utility class to fix this - try { String url = "geojson.json"; ...
Ian Turton's user avatar
  • 79.9k
5 votes

Given a GeoJSON file how do I calculate the area of the embedded features?

You can do this several ways, I think that the easiest (if you only have a few GIS things to do) is to use Turf see here There are also a couple of GIS library whom are a bit heavier (size wise) ...
julsbreakdown's user avatar
5 votes
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How to combine LineStrings using JTS

I think your problem is that none of your strings overlap so there is nothing for the union to do. I've tried the following code: SimpleFeatureIterator itr = features.features(); ArrayList<...
Ian Turton's user avatar
  • 79.9k
5 votes

Looking for the simplest way to get elevation for a give wgs84 coordinate

You can download elevation data in raster format from this url Load each tif into postgres with:- raster2pgsql -d -s 4326 -t 50x50 <TIFF>.tif <YOUR TABLE> | psql -n <YOUR DATABASE>...
CitizenFish's user avatar
5 votes
Accepted

Reproject features with geotools

This code works for me: public static void main(String[] args) throws IOException, NoSuchAuthorityCodeException, FactoryException { if(args.length==0) { System.err.println("usage: ...
Ian Turton's user avatar
  • 79.9k
5 votes
Accepted

SQL injection with ST_geomFromGeoJson

It depends on what your library is actually doing with that query. If it's taking your GeoJSON input and slamming it all into a SQL string, then yes, it's an injection vector, but then so would any ...
Paul Ramsey's user avatar
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5 votes
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Remove/Fill holes in Polygons from a MultiPolygon using JTS Topology Suite programmatically

Basically, you need to create a new Polygon from the ExteriorRing of the input Polygon. gf.createPolygon(p.getExteriorRing().getCoordinateSequence()); There is a little more work with MultiPolygons ...
Ian Turton's user avatar
  • 79.9k
5 votes
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How to convert GeoJSON to GeoTIFF

With the command line, https://gdal.org/programs/gdal_rasterize.html With Python, you can use gdal.RasterizeLayer like in the tests from GDAL e.g https://github.com/OSGeo/gdal/blob/master/autotest/alg/...
ThomasG77's user avatar
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5 votes
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PSQLException: ERROR: operator does not exist: public.geometry && public.geometry

Thanks @CL for Hint, search_path in java solved the problem, you can add comma separated multiple schema in currentSchema connection string parameter old connection url url: jdbc:postgresql://...
swan's user avatar
  • 193
4 votes

converting/parsing geojson into com.vividsolutions.jts geometry

There seems to be nowadays also native GeoJSON reader/writer code in JTS trunk: https://sourceforge.net/p/jts-topo-suite/code/HEAD/tree/trunk/jtsio/src/main/java/com/vividsolutions/jts/io/geojson/ ...
user30184's user avatar
  • 62k
4 votes

Point to Line Calculations

I would recommend to rely on GeographicLib implemented by Charles Karney which uses Gnomonic projection for point to line projections in WGS-84 (http://geographiclib.sourceforge.net/). This solution ...
sema's user avatar
  • 435
4 votes

Unit of Geotools' getArea function

As all of the questions you have linked to say JTS does not care about the units of your data and treats them all alike - so the answer to your question is square degrees. Now that is rarely (if ever) ...
Ian Turton's user avatar
  • 79.9k
4 votes

library to create static maps (an image) with custom map features

If your interested in using a microservice that you can run yourself, instead of a library check out https://github.com/trailbehind/StaticMapService/. You can install background layers into it, then ...
Jesse Crocker's user avatar
4 votes
Accepted

Exporting Shapefile to SVG using Java & GeoTools?

Have a look at the code referenced in my blog post which shows how to do exactly this, including styling the layer. Here is the actual code: private void exportSVG(File file) { Dimension ...
Ian Turton's user avatar
  • 79.9k
4 votes

PostGIS: ST_Within returns "t"/"f" letters instead of "true"/"false" booleans

If you change the line System.out.println(resultSet.getString(1)); to System.out.println(resultSet.getBoolean(1)); you will get back a boolean value instead of a string.
Ian Turton's user avatar
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4 votes
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Why modes are represented with numbers, that are powers of 2.?

So that we can combine them with the bitwise-or operator and then separate them later. For instance, MODE_TRAINISH = MODE_TRAM | MODE_RAIL | MODE_SUBWAY | MODE_FUNICULAR | MODE_GONDOLA; If we ...
Anuraj's user avatar
  • 173
4 votes
Accepted

GeoWebCache Upgrade Error

A quick google of Unsupported major.minor version 51.0 leads to How to fix: Unsupported major.minor version 51.0 error?. Basically you need Java 7 for recent versions of GeoWebCache (and GeoServer and ...
Ian Turton's user avatar
  • 79.9k
4 votes
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is it possible to store empty geometries in an Oracle Database?

This is the question/response I got from oracle's spatial expert in Europe in 2014. q: Does oracle have the concept of an empty geometry? If so can you give me an example? Would this be a valid way ...
aileen's user avatar
  • 104
4 votes
Accepted

How to calculate cell tower polygon and get the coordinates in wkt format

This is a fairly simple operation in Java using GeoTools. All you need to do is start at the tower and travel out a distance (radius) in the direction (azimuth) - probably minus some width parameter, ...
Ian Turton's user avatar
  • 79.9k
4 votes
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Modifying feature attributes of a shapefile in geotools

The only way to make these changes persistent is to write them out to disk (in any format you like). There is nothing to stop you using the same filename as you read in (if you feel brave) but making ...
Ian Turton's user avatar
  • 79.9k

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