Tag Info

Hot answers tagged

11

There are lots of free GIS tools available. One of the imho best is QuantumGIS: http://www.qgis.org. It is available for win/mac and linux. But maybe you prefer openjump a tool written in java, which has special strengths in editing, topology-checking: http://www.openjump.org/ Also take a look at: http://freegis.org/


9

A great GIS that has a huge amount of functionality is QGIS. It is very easy to install especially if you use the osgeo4w installer (Windows). You can use it to view your GML file too. OSGeo is the place you want to look for OpenSource (free) GIS tools and libraries: http://www.osgeo.org/. You will find a ton of stuff here plus links to QGIS and other ...


8

You might want to try Orfeo Toolbox. OTB is based on the medical image processing library ITK and offers particular functionalities for remote sensing image processing in general and for high spatial resolution images in particular. Targeted algorithms for high resolution optical images (SPOT, Quickbird, Worldview, Landsat, Ikonos), hyperspectral ...


7

Refractions Research has made a Line Cleaner tool that seems to do what you want. Line Cleaner cleanses networks by simplifying complex, cyclical, very short and zero-length geometries, and removing pseudo-nodes and insignificant vertexes. Most significantly, in the cleansing phase, it is able to ensure that feature matches can be considered ...


7

Maybe these links will help you: How to build effective heat-maps? with QGIS: http://alexsciuto.com/blog/2010/11/how-to-make-your-own-heat-map-pt-1-gathering-the-materials/ Python script: http://www.sethoscope.net/heatmap/ http://sk53-osm.blogspot.com/2011/01/heat-maps-from-osm-pois.html Sorry for a non elaborated answer..


6

Most of these recommendations are not open-source, but they are free and add a lot of useful functionality to ArcMap. Geospatial Modeling Environment - Written for ArcView (works with all licenses though), adds some functionality that is available in ArcEditor and ArcInfo. Not open-source (uses R, which is open-source though), but free. ET Tools (GeoTools, ...


5

Draftsight http://www.3ds.com/products/draftsight/draftsight-overview/ or even better DoubleCAD http://www.doublecad.com/Products/DoubleCADXTv3/tabid/1100/Default.aspx


5

Hossein, combining spatial maps with databases is the heart of GIS. Practically any GIS will allow you to do both of those things in a variety of ways - though a desktop interface, programatically, served remotely, etc. Here is an excellent list of free and open source desktop GIS packages. Quantum GIS, with a powerful collection of tool and an easy-to-use ...


5

Did you try Qgis? I think wil cover you. You wil find a lot of help on Internet. It is very easy to manipulate the data. If you want to change their style or icons it is very easy. And of course Tiff export is a standard. Is open source and cross platform, that mean you can install it in any Opereting System. More info: From here Download: From here ...


5

Here a generic soluion, that you can impĺement with PostGIS or any other OGC-compliant software. NOTE: as I say before, a key concept in FOSS and GIS is standardization: the best solutions adopt standards, like OGC ones. Your problem is to "find pseudo nodes"... But I think that it is a little more, "find non-pseudo nodes and join lines of pseudo ...


5

Here's one possible solution: Digitize the features in QGIS (which is free software) Use SQL Server 2008 Spatial Tools (free), Shape2SQL in particular, to import your resulting shapefile(s) you created in QGIS into SQL Server Some Googling or searching on this site will get you links to other QGIS tutorials on digitizing and just using QGIS in general.


4

Keep in mind - no one procedure is necessarily going to provide the "best result." Image interpretation is critical, both before and after classification. You will likely find urban areas misclassified as something else and non-urban areas classified as being urban. You have two basic approaches: 1) Supervised classification: this involves selecting ...


4

Let's narrow down the methods of classification to two major groups: object-oriented classification and pixel-based classification. The attached tables are from a publication titled Comparison of Pixel-Based and Object-Oriented Classification Approaches using Landsat-7 ETM sPECTRAL Bands. The highlighted row in Table 3 shows that object-oriented ...


3

Also, if you do not mind some scripting in Python, there is Shapefile module for this. Small example, create .shp with point features from coords in .xls: import xlrd import shapefile Path = "c:/" f = "Excel_w_coords.xls" # Open Excel workbook wb = xlrd.open_workbook(Path + f) # List all sheets in Excel list = wb.sheet_names() for i in list: sh ...


3

The OpenStreetMap (OSM) editor JOSM is a great tool for digitising. Although it is specifically developed for editing data in OSM it can save data as .osm or GeoJSON files which can then be converted to other GIS formats (e.g. using ogr2ogr). This export facility converts it into a good general purpose digitising package.


3

You could take a look at Sextante which makes SAGA and GRASS functionality available through ArcGIS 10. You can also install SAGA separately and run it from ArcGIS using the command line. Both give you alternatives to a lot of Spatial Analyst type features.


3

GRASS GIS can do the same job: http://grass.osgeo.org 3D tutorial volume calculation: r.volume nviz visualization tool:


3

If you are open to scripting, I've used several Python libraries to process large (>30 million points) LAS point clouds. The best one I've found is laspy. It easily reads LAS files into a numpy array, and from there its as simple as filtering and writing to a new file.


2

You can have a look in GvSIG (OADE version), it starts to have good build-in tools for CAD, so : it has a command line tools to edit every points (with some topology functions) it opens .dwg, .dxf and .dgn files it generates world files for raster georeferencing it integrates like Kosmo, Sextante and now Grass for the OADE version so you can make profile ...


2

I've never tried it, but here is mention of sketchup on linux. You can place a sketchup model into google earth.


2

I'm assuming you want a density map of how "well covered" each area is, i.e. how many offices it is near, incorporating the "radius" of those offices? You can actually do all this within PostgreSQL, or at least within PostGIS, which is a free extension. I suggest you get hold of that, and read up on some of the docs. You will probably then need to geocode ...


2

You can download city data from Natural Earth Data site: Populated Places Raster maps you can use as a background You can use all files from that site with QGIS but any other open source GIS should be fine. There are many possible ways to navigate to a given city. For example, QGIS "Find by attribute" plugin lets you search for a city by it's name and ...


2

In GRASS-GIS version 7.0 (a FOSS package -- not only freeware), still the development version, though fully working and more or less for production-workflows ready, there is i.segment. More upon the module and its implemenation in a dedicated GRASS-Wiki page (along with some sample screenshots). At its current state, the module does (as per the module's ...


2

I just thought of a fairly simple solution, which assumes the comment I posted on the question is correct: It sounds to me like every single paved street must be connected in a single network. Any paved street not connected to that network must have been mistakenly given the "paved" attribute. If so, in ArcGIS you can use the Dissolve tool, dissolving ...


2

It isn't very fancy, but depending on how your line data is drawn it may work: 1) Use the Unsplit Line tool on your road file and have your dissolve field be your paved/unpaved field in your table. This means you will have one large object representing the connected paved roads. 2) Select all paved roads in the new file. 3) Manually remove the large object ...


2

While ArcGIS can certainly perform the work you want, if you have access to other software, I would use those. I have not used GRASS before for image classification, but I know it is more than capable. From my knowledge, Ecognition is more for object based classification. I have used ENVI for image classification a few years ago and it does the job really ...


2

Thanks for the list. However i don't see the defined problem, because basically what you ask is that people search/google for you. For now i go along with your request, but you could do that yourself. In general as you already mentioned the best software is only available for windows systems and you might get along with using WINE for your problem. Besides ...


2

Based on Barbarossa's answer, I managed to put together this rather inefficient but sometimes functional Python script. It uses the laspy library. It is memory intensive and may fail when ran on 32bit versions of Python. I actually ran out of memory when processing a file of 10M points. import numpy as np from laspy.file import File inFile = ...


1

In GRASS GIS, you can use v.edit for this. There is " snap: Snap vector features in given threshold" along with the possibility to define a box or polygon to spatially constrain the snapping to a certain area in the map as well as "where" to constrain with attribute selection.


1

Here are steps to Find your pseudo nodes using OpenJump a free GIS. QGIS and gvSIG have the Sextante Plugin, so these same steps should work their too, the Spatial Join might be slightly different. I used version 1.2 for testing. -- save the Line endpoints Sextante toolbox, Topology, Extract endpoints of lines -> endpt_0 -- unsplit your lines Sextante ...



Only top voted, non community-wiki answers of a minimum length are eligible