Proj4 String To Epsg

bs sqlite database. When attempting to reproject a GeoTIFF raster to Stereographic SRS using a Proj4 string, the actual resulting Raster has an Oblique_Stereographic WKT. Projection definition class. The value needs to be in the same units as the requested image projection. proj4_string. 设置环境变量 set GDAL_DATA=\ms4w\gdaldata path=%path%;\ms4w\tools\gdal-ogr;\ms4w. The syntax of this format is epsg: or esri:, where is a 4-6 digit for the desired coordinate system. gdb as a new TileMill layer. Other web services can be found using an online search. Originally a port of PROJ. One proj4 representation of this projection is: "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs". WGS84 Bounds: -180. There are actually 5 EPSG valid transforms for this datum. In following example we use Proj4 string to initialize the projection crs = QgsCoordinateReferenceSystem () crs. These are equivalent, but look a little different. 21 SDO_CS Package (Coordinate System Transformation). The basis for my optimism is that one can convert from epsg to proj4 via GDAL and than convert that proj4 string. In addition, proj4 strings should be supported by back-ends. ST_Transform actually changes the coordinates of a geometry from one spatial reference system to another, while ST_SetSRID() simply changes the SRID identifier of the geometry. INTERGEO OSP '08 Fitzke: deegree CRS 2008-09-30 gesellschaft für raumbezogene informationssysteme mbH Koordinatentransformationen im Griff Die neue CRS-Komponente im deegree-Projekt. For questions or comments about this dataset, contact the administrator of this server [Support] at: [email protected] All keys are checked against the all_proj_keys list. statewide_proj State plane zone for projecting the entire state. sudo apt-get remove libproj-dev Secondly, adding my compiled proj4-4. In order for query string data to be accepted, it must be defined as described in the task query parameters section. 对于非地理专业的开发人员,对与这些生涩的概念,我们不一定都要了解,但是我们要理解,凡是以经纬度为单位的都是地理坐标系,因为它归根结底是一个椭球体,只不过各个国家为了反映该国家所在区域地球的真实形状,而. It seems to work in R so I am happy with the result. Transform coordinates Online convertor for lat & long coordinates, geodetic datums and projected systems. When I try the other gsb file the datum transformation is couple of 100 meters of. This is a very typical way how CRS is stored in GeoDataFrames. epsg (int, optional) – The EPSG code of the CRS. Several projections can be definied but the projection set as projectionCode will be the map projection. 주요 좌표계 EPSG코드 및 proj4 인자 정리 [2] 2011-03-03 15:53:11. 4 string into a mapping of parameters. - v , -- verbose - d , -- debug - tags Output the tags for every feature parsed. Bearing and distance: As of 2011 there is a new package geosphere with many spherical trigonometry functions, including bearing() and distCosine(). As with ggplot2, map elements are layered in the order in which they are called. in_crs_string (str) – An EPSG, PROJ, or WKT string. In PROJ, a conversion or transformation is defined by a “proj-string”. The acronym EPSG, comes from the, now defunct, European Petroleum Survey. I've written a small perl script to handle converting the coordinates in shapefiles to a different coordinate set. eu ADAGUC is used as a central component, so for NMDC these additional attributes are highly recommended. Horizontal component of 3D system. These can be defined using the Proj notation (see Proj4 documentation for details) but it is easier to set up commonly-used projections by referring to their standard code numbers. It all depends on how you define the 3021 spatial reference system. 3, for compatibility with Leaflet 0. if you do not want to download anything, Proj4js is also hosted on cdnjs for direct use in your browser applications. When parameters were read from EPSG CSV files the standard parallels and origin were mixed up. 4 definitions. 4 by reversing the sign of the rotation vectors. The string will be parsed and the projection and ellipsoid members set and the remainder of the proj4 string will be stored in the parameters member. If I call latitude=a, longitude=b and. axes An ordered list of Axis objects describing X and Y. The second format supported by VA is Proj4, the third link in the image above. You can use it together with one of the following 3 options to get either the proj4 string, WKT definition or EPSG code. The above code includes two working methods - the stylesheet version, though longer, may be useful if you're already processing OSM with XSLT. epsg:4456), a proj4 string, a file containing a proj4 string, "utm" (use local UTM), "file" (use existing), "local" (generate a local projection) -s, --simplify FACTOR Simplify geometries, accepts an integer between 1 and 100, the percentage of each geometry to retain. There is also another typical way of representing the coordinate reference system, namely storing that information in Proj4-string format (we will come back to this later). shp test_TNT. ##### # # CMake main configuration file to build GeoTIFF library and utilities. GeoJSON can be used to represent a geometry, a feature, a collection of geometries, or a collection of features. The slight modifications are binary-compatible. The get() function will accept any of the SRS representations we discussed above: WKT, PROJ4, EPSG, or Aliases. On Ubuntu, provided you have the python-gdal package installed, the above files executed by python will accept the first argument as a wkt/proj projection string, and return the proj/wkt equivalent. Installing. But the problem is in the way how QGIS copes with spatial references. 주요 좌표계 EPSG코드 및 proj4 인자 정리 [2] 2011-03-03 15:53:11. Once you've found the projection you want, you can create the appropriate CRS object using one of two codes - the proj4 string, or the EPSG code. , specifying the epsg code), is that it's usually much shorter than the proj4 string, while both methods provide basically the same information. This data frame includes state abbreviations, EPSG codes, and proj4 strings for projections from the State Plane Coordinate System. The Registry included is initialized on startup with specific PTV coordinate reference systems as well as other well known systems taken from an internal EPSG database, defining the coordinate reference systems in the Proj4 well known text format. Bare parameters like "+no_defs" are given a value of True. One proj4 representation of this projection is: "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs". The EPSG code may not always be available for a particular coordinate system, but if a spatial object has a defined coordinate system, it will always have a PROJ4 projection string. The image will be resampled using bilinear resampling. The epsg code or proj4 string can be found either in the ArcGis data definition or by using a web service (for example, spatialreference. axes An ordered list of Axis objects describing X and Y. I have no problems compiling libTiff and Proj4 as is but I had to modify the libGeotiff's makefile. There are actually 5 EPSG valid transforms for this datum. The shapefile should have a. I understand your idea. I have been playing around with raw proj 4 but it really matters which of the two files is used for the nadgrids parameters. If specified , overrides projection from source metadata if it exists. A CRS represents a simple Cartesian coordinate system. add_deviation (dev, td=None) [source] ¶. EPSG A 1-, 2-, or 3-dimensional cartesian coordinate system. If orig_proj4_string or dest_proj4_string argument is passed but is NULL instead of string, the projection. Only as much of the input string as needed to construct this SRS is consumed from the input string, and the input string pointer is then updated to point to the remaining (unused) input. prj file is present for a *. csv files in this directory are an extract of tables from the EPSG projection database in CSV (comma separated value) format. A data frame with 123 rows and 5 variables: state. Data Tip: the last portion of each proj4 string is +towgs84=0,0,0. These are called EPSG codes and can be looked up on spatialreference. Whenever possible, it is recommended to use EPSG codes instead of proj4 strings. I know it handles EPSG codes. Click a link that says Proj4 and you will get the correct proj4 text presentation for your projection. , specifying the epsg code), is that it's usually much shorter than the proj4 string, while both methods provide basically the same information. EPSG Tables ===== VERSION: 9. 실습순서 • VWORLD 키 획득 • VWORLD API 연동 클래스 설명 • 주소에서 위경도 가져오기 실습 • 위경도 에서 주소 가져오기 실습 • 구글 에서 고도 값 가져오기 실습 • proj4. ST_Transform is often confused with ST_SetSRID(). GeoJSON can be used to represent a geometry, a feature, a collection of geometries, or a collection of features. But when I try to change the definition in 0. org service to upload the. On a side note, if you're ever just wanting to transform coordinates, pyproj supports generic proj4 strings. 6 <–> WKT/PROJ. You can use it together with one of the following 3 options to get either the proj4 string, WKT definition or EPSG code. This format consists of a string of space-delimited name value pairs. add_deviation (dev, td=None) [source] ¶. This ensures applications like TileMill can avoid unneeded projection. prj file and get a list of matching EPSG codes. ETRS89 IS a datum, also known as a reference frame. The spatial reference identification system is defined by the European Petroleum Survey Group (EPSG) standard, which is a set of standards developed for cartography, surveying, and geodetic data storage. exe to make a transform. class pyepsg. Scientists blog from Antarctica and provide a glimpse of what it's like to do research in the field. Spatial reference systems can be referred to using a SRID integer, including EPSG codes defined by the International Association of Oil and Gas Producers. Thanks for the reply my main objetive is make a static library. It is the standard of world maps made by the National Geographic. How to import Spatialite into PostGIS using ogr2ogr GOAL: Import a Spatialite table into an existing PostGIS table appending (inserting) new rows using ogr2ogr. If you want to convert your sf point objects to a data frame with coordinates, you can use the st_write() function with a hidden argument (these are arguments associated with an external utility called GDAL and so they're not in the R help) to force sf to include the coordinates in the. # # Author: Mateusz Loskot # ##### PROJECT(GeoTIFF) SET(GEOTIFF_LIB_NAME geotiff) SET. Methods initialize signature(. Re: [Geoserver-users] Problems reprojecting to Google Maps projection EPSG:900913 Re: [Geoserver-users] Problems reprojecting to Google Maps projection EPSG:900913. 5 gon V" SRID 3021 appears to be standard for Sweden Nationally Here is a test case:- Search for benarp5389. We use cookies for various purposes including analytics. conf) under the path of '/etc/ld. Function parse_proj4 gets the proj4 string from a space-time object and check_projection checks if the input projection is compatible with the referent projection system. Add a deviation survey to this instance, and try to compute a position log from it. Dictionary of PROJ parameters. Create a new TileMill project called gdb-cal-fire. I mean, we should add this information to the Proj4 string - or even the information about switch axis. GeoJSON is a data-interchange format for a variety of geographic data structures. This site should be able to give you a proj4 string if you’re lazy like me and want to just copy it. Lunaserv Configuration Documentation This is the proj4 string for this SRS. 234 : * 235 : * The OGRSpatialReference is initialized from the passed PROJ. By default, OpenLayers ships with the ability to transform coordinates between geographic (EPSG:4326) and web or spherical mercator (EPSG:900913 et al. They are extracted from open source Python projects. py, which contains a dictionary, prj, of projection file text keyed by epsg value. Download files. There is a small problem with the gui : if you select Source Projection > Projection, then EPSG Code, then Projection again, the focus stay on EPSG Code. Indeed, for this specific deposit, an alias has been created to simplify the writing. The methods are otherwise the same. if you do not want to download anything, Proj4js is also hosted on cdnjs for direct use in your browser applications. - p PROJ4_STRING , -- proj4 = PROJ4_STRING PROJ. Consult also the OGC WKT Coordinate System Issues page for implementation details of WKT in OGR. About the EPSG Dataset The IOGP's EPSG Geodetic Parameter Dataset is a collection of definitions of coordinate reference systems and coordinate transformations which may be global, regional, national or local in application. Rather than writing out the whole PROJ4 string, we can use an EPSG code as shorthand for it. I hope this is useful to others wanting to use a projected version of an OSM extract. proj4_string The PROJ4 string for the state plane projection. 4 string into a mapping of parameters. Only as much of the input string as needed to construct this SRS is consumed from the input string, and the input string pointer is then updated to point to the remaining (unused) input. On Thin Ice: Expedition to a Crumbling Ice Shelf. Accepts either an EPSG code (e. Convert CRS to a PROJ4 dict. The acronym EPSG, comes from the, now defunct, European Petroleum Survey. Where does the data come from and what does it do? In many cases, a spatial database will prepopulate spatial_ref_sys for you with a standard set of EPSG data. If orig_proj4_string or dest_proj4_string argument is passed but is NULL instead of string, the projection corresponding to original or destination SRID is used. 6 <–> WKT/PROJ. It represents the total land cover area for the GLOBIOM's CRs. 设置环境变量 set GDAL_DATA=\ms4w\gdaldata path=%path%;\ms4w\tools\gdal-ogr;\ms4w. "wintri" Winkel Tripel (1921). Geobricks Proj4 to EPSG code convert library. Converting WKT projection info to Proj4 (and back) I've had many occasions where I've had WKT-style projection text (e. shapefile_utils. 6 <-> WKT/PROJ. The string will be parsed and the projection and ellipsoid members set and the remainder of the proj4 string will be stored in the parameters member. Note that successful compilation does not necessarily mean the 64 bit executables will run successfully. the last portion of each proj4 string is +towgs84=0,0,0. an EPSG code. Performance. Default is "Metric". Whenever possible, it is recommended to use EPSG codes instead of proj4 strings. To add a lat/long graticule, use the tm_grid() function. CartesianCS(element) Bases: pyepsg. the last portion of each proj4 string is +towgs84=0,0,0. If orig_proj4_string or dest_proj4_string argument is passed but is NULL instead of string, the projection corresponding to original or destination SRID is used. io/ から引っこ抜いてく…. Finally, I sovled this issue. You can also build your own image. As a valued partner and proud supporter of MetaCPAN, StickerYou is happy to offer a 10% discount on all Custom Stickers, Business Labels, Roll Labels, Vinyl Lettering or Custom Decals. Provided that an EPSG database is available, Apache SIS CRS. The manual page of readOGR states: p4s PROJ4 string defining CRS, if default NULL, the value is read from the OGR data set then, if a *. org) or, as a downloadable zip files, through IOGP's EPSG home page at www. prj file which defines the projection. This ensures applications like TileMill can avoid unneeded projection. You can vote up the examples you like or vote down the ones you don't like. AWIPS Projection Data. if you do not want to download anything, Proj4js is also hosted on cdnjs for direct use in your browser applications. In following example we use Proj4 string to initialize the projection crs = QgsCoordinateReferenceSystem () crs. net from Pulkovo 1942 / Gauss-Kruger zone 14 (EPSG 28414) -> Pulkovo 1942 (EPSG 4284) -> Pulkovo 1942 /. add (epsg, prj) ¶ add an epsg code to epsgref. PROJ is a generic coordinate transformation software that transforms geospatial coordinates from one coordinate reference system (CRS) to another. net 과 geoapi. Now, reading online I've found out the issue is that the EPSG:28992 Proj4 string redirects coordinates to a system that's not the same as our view. Hi, I'm an astronomer and I'm exploring the possibility of using GIS tools (specifically spatialite at the moment) with astronomical objects. My recommendation is to always use EPSG:25832. prj file which defines the projection. Be familiar with the proj4 string format which is one format used used to store / reference the CRS of a spatial object. for /R %I in (*. remove (epsg) ¶ removes an epsg entry from epsgref. Provided by: libgeo-proj4-perl_1. an EPSG code. Once proj4 string is read, QGIS searches for a SRS ID in SRS database. Bare parameters like "+no_defs" are given a value of True. Download files. CRS units type for coordinates conversion (one of control options. If there is a corresponding EPSG code, it will be used. --from=crs-name is the CRS to convert the GeoJSON from; either a name from crs-defs, or a Proj4 CRS definition string--to=crs-name is the CRS to convert the GeoJSON to; either a name from crs-defs, or a Proj4 CRS definition string--use-epsg-io or --eio to use epsg. Declaration. One pulls a pre-built image from the docker hub. The raw GINI data files are provided on predefined grids used by the National Weather Service AWIPS system. The manual page of readOGR states: p4s PROJ4 string defining CRS, if default NULL, the value is read from the OGR data set then, if a *. get_spatialreference (epsg, text='esriwkt') ¶ Gets text for given epsg code and text format from spatialreference. 2011-01-28 11:53:53. It is based on R, a statistical programming language that has powerful data processing, visualization, and geospatial capabilities. There are actually 5 EPSG valid transforms for this datum. To change the projection, pass the PROJ4 string to the projection parameter. If you come across some transformation issues on precision when dealing with UTM, I’ll recommend using the Engsager Extended Transverse Mercator implemented in proj4. 다양한 좌표계 변환을 제공하는 라이브러리 자유롭게 인자를 지정하여 표준이 아닌 좌표계 간 도 변환 가능 USGS의 Gerald Evenden에 의해 만들어진 오픈소 스 라이브러리 현재 OSGeo 프로젝트 중 하나이며 MIT 라이센스 GeoServer, OpenLayers, PostGIS, QGIS. scope¶ A human-readable description of the intended usage for this CRS. Do not include the 'EPSG:' prefix. 6 Xsize: 4720 Ysize: 5544 Map projection: Stereographic Proj string: +proj=stere +lon_0=0 +lat_0=90 +lat_ts=60 +ellps=WGS84 +towgs84=0,0,0 +units=km +x_0=2526000. Depending on your preferences. There are known to be problems with some coordinate systems, and any coordinate systems with odd axes, a non-greenwich prime meridian or other quirkyness are unlikely to work properly. conf echo 'the lib. Re: [Geoserver-users] Problems reprojecting to Google Maps projection EPSG:900913 Re: [Geoserver-users] Problems reprojecting to Google Maps projection EPSG:900913. Bearing and distance: As of 2011 there is a new package geosphere with many spherical trigonometry functions, including bearing() and distCosine(). Features that cannot be transformed are returned as empty geometries. Other web services can be found using an online search. Using Golang with Proj4 to convert between OSGB and WGS84 (both to and from) - osgb. These can be defined using the Proj notation (see Proj4 documentation for details) but it is easier to set up commonly-used projections by referring to their standard code numbers. It seems that SQLAnywhere gives incorrect results when converting from WGS84 to RT90 (a common Swedish coordinate system) There are a couple of RT90 variants depending on location but "RT90 2. ST_Transform is provided by a separate plugin named v7proj4, as described below. In order for query string data to be accepted, it must be defined as described in the task query parameters section. to_string ¶ Convert CRS to a PROJ4 or. Popular projection that is useful in world maps. indoor maps, game maps). - EPSG codes are simply used to generate proj4 string and then this string is parsed, I suspect that the EPSG could be used to directly fill the projection parameters There is an option for that too, even compile time. The database is located in the site packages folder in epsgref. io 的頁面下面有一堆 Definition 提供, 用來幹嘛? 當然是轉換了! 當中最 Programmer Friendly 的應該是 proj. ETRS89 IS a datum, also known as a reference frame. In GDAL as well as QGIS it is set by the environment variable OSR in the settings or in a custom proj definition string +proj=etmerc etc. Input dataset will be transformed to this coordinate reference system. We include the definitions from EPSG as of some point in time. This is a conversion factor that is used if a datum conversion is required. Ik draai Ubuntu 12. io/ that makes the search of a specific projection very efficient. If you need support for tile layers in other projections, the Proj4Leaflet plugin lets you use tiles in any projection supported by Proj4js, which means support for just about any projection commonly used. QGIS doesn't recognize this CRS, because epsg_tr. Proj4 string values can be received via epsg['epsg-code-here']. --from=crs-name is the CRS to convert the GeoJSON from; either a name from crs-defs, or a Proj4 CRS definition string--to=crs-name is the CRS to convert the GeoJSON to; either a name from crs-defs, or a Proj4 CRS definition string--use-epsg-io or --eio to use epsg. We use cookies for various purposes including analytics. The epsg code or proj4 string can be found either in the ArcGis data definition or by using a web service (for example, spatialreference. 3, for compatibility with Leaflet 0. epsg:4456), a proj4 string, a file containing a proj4 string, "utm" (use local UTM), "file" (use existing), "local" (generate a local projection) -s, --simplify FACTOR Simplify geometries, accepts an integer between 1 and 100, the percentage of each geometry to retain. Since the pro4 string describes the OSTN15 datum you should specify the file OSTN15_NTv2_OSGBtoETRS. epsg The EPSG code for each state plane zone. Name of the state plane zone. The shapefile should have a. Raster Reprojection. CRS label to be displayed in control. Used by the GPS satellite navigation system and for NATO military geodetic surveying. the last portion of each proj4 string is +towgs84=0,0,0. Add in the line #define BUILD_AS_DLL 1 as shown in red below. find­Operation(…) method produces results that are closer to the authoritative definitions of coordinate operations (technically, Apache SIS referencing engine is a late-binding implementation while Proj. An authority string [i. Hi, I am working with PROJ Rel. Even better, never tried but I'm convinced it's possible, we would be able to use EPSG codes directly. You can use these in applications, but this is not required, as API params and options use module:ol/proj~ProjectionLike which means the simple string code will suffice. Note: the input code is not validated against an EPSG database. The simplest way to use the tool is to supply the input coordinates on the command line itself. Proj4js is a JavaScript library to transform point coordinates from one coordinate system to another, including datum transformations. PyCRS package is a handy library for dealing with projections. Re: [Geoserver-users] Problems reprojecting to Google Maps projection EPSG:900913 Re: [Geoserver-users] Problems reprojecting to Google Maps projection EPSG:900913. This tutorial describes and demonstrates some of the capabilities the drivers provide, points out items to be aware of when using the drivers, and hopefully provides some examples you can use to get what you need out of the LAS drivers. proj4 package contains a slightly modified copy of the classes provided in the jniwrap directory of the Proj. One of these is created for each projection supported in the application and stored in the module:ol/proj namespace. There is also another typical way of representing the coordinate reference system, namely storing that information in Proj4-string format (we will come back to this later). class pyepsg. Retrieves the proj4 projection parameter string for an authority and coordinate code Get the proj4 projection string for the EPSG code. Default is "Metric". epsg The EPSG code for each state plane zone. If I call latitude=a, longitude=b and. an EPSG code. For each member, the name is always a string. These provisional mappings have been compiled to support, among other things, CF proposals 69 and 80; which have been incorporated in the CF Conventions document version 1. Thanks for the reply my main objetive is make a static library. if you do not want to download anything, Proj4js is also hosted on cdnjs for direct use in your browser applications. Return type. Where does the data come from and what does it do? In many cases, a spatial database will prepopulate spatial_ref_sys for you with a standard set of EPSG data. 21 SDO_CS Package (Coordinate System Transformation). scope¶ A human-readable description of the intended usage for this CRS. Proj4 strings are commonly used in OGR to represent the Spatial Reference of spatial features and looking up the EPSG code for a Proj4 string is easy using Linq (Language-Integrated Query) and Regular Expressions in C#. 4 software for the transformation. Paste a WKT definition or type keywords below : or upload a. add_deviation (dev, td=None) [source] ¶. This data frame includes state abbreviations, EPSG codes, and proj4 strings for projections from the State Plane Coordinate System. Extract the Proj4 source code into a folder e. io Find an R package R language docs Run R in your browser R Notebooks. With my previous set up one one of the main difficulty was to find the right proj4 string //epsg. Raster Reprojection. 1), but the About box of QGIS shows: Compiled against PROJ5. epsg - Mappings of EPSG integer string keys to Proj4 strings values. prj file which defines the projection. It seems to work in R so I am happy with the result. I've got it working, but the reprojection is still not quite correct. Installing. EPSG 4326 to 3857 works on X axis but not Y with PROJ4NET. To add a lat/long graticule, use the tm_grid() function. When I try the other gsb file the datum transformation is couple of 100 meters of. Default is system. It is the standard of world maps made by the National. Load PostGIS geometries in R without rgdal. 4 definitions. Bare parameters like "+no_defs" are given a value of True. They are extracted from open source Python projects. - p PROJ4_STRING , -- proj4 = PROJ4_STRING PROJ. io to look up any CRS definitions that aren't already known. For example a widely used identifier is EPSG:4326. ” Note: I am not going to use SRID for this example as it is not required in current scenario but while working with real application you must consider the same. 8 / Zanzibar the first time to load a data in our national CRS (EPSG:28992) you are being presented with the following dialog: I thought it had something todo with the fact that this OSGeo4W install maybe used the newer PROJ (6. Paste a WKT definition or type keywords below : or upload a. Transform your coordinates online easily with epsg. 0 id The EPSG code for this CRS. They are extracted from open source Python projects. Popular projection that is useful in world maps. Whenever possible, it is recommended to use EPSG codes instead of proj4 strings. GDAL stands for Geospatial Data Abstraction Library, and is a veritable “swiss army knife” of GIS data functionality. You can also build your own image. the last portion of each proj4 string is +towgs84=0,0,0. epsg (int, optional) – The EPSG code of the CRS. Usage ## S4 method for signature 'Spatial' getCRS(obj) ## S4 method for signature 'Raster' getCRS(obj). Gets the proj4 string from a object of type "Spatial" or "Raster". Provided by: libgeo-proj4-perl_1. 04 (undefined to reference to 'pj_ctx_fclose') r,gdal,rgdal,proj4. Type: compromise "robin" Robinson. OpenLayers 3 has an ability to display raster data from WMS, WMTS, static images and many other sources in a different coordinate system than delivered from the server. proj4_string The PROJ4 string for the state plane projection. Alternative to the epsg parameter [optional] bounds - value:,,, - bounding box used for spatial filtering. This is likely to be the only class you need to work with in Proj4Leaflet, unless you have special requirements.