A spatial operation in which two or more maps or layers registered to a common coordinate system are superimposed, either digitally or on a transparent material, for the purpose of showing the relationships between features that occupy the same geographic space.

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1
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2answers
443 views

Calc vs. Overlay for speeding up band math in R 'raster' package?

Regarding yesterday's question about how to speed up band math in the R 'raster' package, would it be the same to use overlay to calculate NDVI instead of calc? If that's not the case, what's the ...
4
votes
3answers
4k views

OpenLayers: Showing a WFS overlay on top of Google Maps

I have found similar questions asked previously, but I still fail to get a simple WFS point layer to work using OpenLayers and Google Maps. The original code I used was based on WFS polygon layers I ...
3
votes
2answers
663 views

Overlay Vector Layer on Raster Layer

How can I overlay a Vector Layer on a Raster Layer and assign NoData Values on the Raster where the Vector Layer does not cover the Raster Layer? (preferable with ArcGIS)
5
votes
1answer
331 views

What tool do I need to have satellite background images to draw features of a postgis database?

What tool do I need to have satellite background images to draw features of a postgis database? I looked about Geomajas but seems very complex for what I'm trying to do. I have osm data imported in ...
0
votes
1answer
777 views

In leaflet does the addControl automatically handle events via the leaflet API?

I need to add additional overlay layers to be controlled by the controls within the leaflet map boundaries, but the code utilizes a leaflet-custom.js file. I am assuming it handles the event and ...
1
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0answers
358 views

Raster Over Layer in Leaflet from GeoServer

I want to add a raster over layer onto the base layer and the raster layer is published by a Geoserver WMS. I set the raster layer's geographic coordinate system as the same as the cloudmate tiles. ...
6
votes
1answer
585 views

overlay county shapefiles for 2 different years

I have county-level shapefile for South Caroline in 1880 and one for 1940. I would like to overlay these two files so that they do the union and indicate the percentage of the land in 1880 that went ...
2
votes
1answer
338 views

How can I enable panning using Openlayers and a vector overlay with controls?

I am creating a map using the following code: map = new OpenLayers.Map({ div: "map" }); Then I load in a geojson polygon layer and add two controls var highlightCtrl = new ...
4
votes
1answer
496 views

Shapefile vs Arrays of coordinates to build Google Maps overlay?

I am very new to GIS, and my task is to overlay about 100 polygons on a map. I'm using Google Maps Javascript API v3. I think I can define all my polygons as sets of lat/long coordinates in my ...
2
votes
3answers
7k views

Can OpenStreetMap be used as a WMS service in MapServer?

I want to produce a png image that uses OpenStreetMap data and has a vector overlaid on the base data. I am able to produce the vector overlay from within Mapserver, but I have difficulty ...
2
votes
1answer
245 views

Overlay analysis of topographic data

I have a topographic map with Buildings, Roads, Hydro and land use as the prominent layers in polygon format. Also i have newly collected Building polygons of the same area in shape file format. Now i ...
0
votes
1answer
272 views

Does a polygon in a layer intersect with another polygon in the same layer [closed]

I am a CS major with little experience in GIS. I am working on vector polygon overlay. Looking at GML and shapefile data, I realized that a map is made up of a large number of polygons. Does a polygon ...
3
votes
2answers
3k views

Load layers only when zoom level is reached

I'm trying to load different layers based on the user zoom level with OpenLayers. I've seen some similar questions in here, but they load the layer and then hide/show it based on the zoom level. I ...
3
votes
1answer
2k views

UK region overlay on map

I'm hoping to overlay UK regions (East Midlands, Wales, London etc) on a Google Map. Ideally the regions could be coloured, opaque and have some form of label. There is no hover / interaction ...
0
votes
1answer
209 views

overlay a county shapefiles for 2 different years [duplicate]

Possible Duplicate: overlay county shapefiles for 2 different years 2 down vote favorite I have county-level shapefile for South Caroline in 1880 and one for 1940. I would like to overlay ...
3
votes
2answers
286 views

calculate coastline at risk

I have an idea of what I want to do but I don't know yet what tools will bring me there. I have administrative boundaries in one layer and coastline in another layer. The coastline is categorized in ...
2
votes
1answer
413 views

Technique using GDAL to overlay / fit one PNG map to directly overlay on another?

I have one .PNG basemap with known North edge of Latitude = 52.48, a South edge of Latitude = 21.94, an east edge of Longitude = -61.87 and a west edge of Longitude = -129.37. And I have another PNG ...
5
votes
3answers
549 views

Can I have Points, Lines and Polygon features in one QGIS layer?

I have a situation where planning is done on a "base map" consisting of rivers, contours, roads etc. There is a need to create a "overlay(s)" over the "base map" consisting of drawings, that could be ...
1
vote
1answer
299 views

Summarize polygon area using another polygon

I have a shapefile representing public/private lands in Montana. This is a multipart shapefile where I've simplified attributes so that #1==private and #0==public. Next I have a shapefile of ...
3
votes
1answer
879 views

Why does my WMS layer overlap the Google Maps v3 logo?

I'm using Google Maps v3 as a base layer and on top of that I create an overlay pointing to my WMS (streets and avenues). A few months ago all works fine, my WMS layer was not overlapping the Google ...
1
vote
0answers
599 views

Zipcode overlay on OSM

I have to display an overlay with different colors depending on the zipcode in Europe. Can I get this information from OSM shapefile ? If yes, how exaclty ? Is there a tutorial somewhere ? Thanks
1
vote
1answer
362 views

How can I move diagrams?

Is there a way to locate diagrams and move them wherever you want in QGIS 1.7.4/ 1.8.0? I created a pie chart under the tab "diagram". I can mark those diagrams with a green box and move them via the ...
1
vote
2answers
2k views

OpenLayers WMS disappears when including OpenStreetMap

Setup: ArcSDE 9.3.2 Oracle 11g GeoServer 2.1.4 OpenLayers (latest build) OpenStreetMap InternetExplorer 7.0/ Google Chrome EDIT: I have updated information just below the screen shots ...
1
vote
1answer
670 views

Can't display overlay

I am trying to add a WMS radar overlay to my map but it won't seem to gather it. noaaRdr = new OpenLayers.Layer.WMS("Latest Radar", "http://nowcoast.noaa.gov/wms/com.esri.wms.Esrimap/obs?", { ...
2
votes
2answers
417 views

count features in polygon shapefile A that fall within each feature of polygon shapefile B

I have two polygon shapefiles, each of which contain multiple (possibly overlapping) polygons. Is there some way, using GRASS, to calculate the number of polygons belonging to shapefile A that fall ...
3
votes
2answers
854 views

Clip depth contour with spatial polygon

I need to somehow combine my Spatialpolygons with my depth contour, but not sure how do to so. Maybe create a SpatialPolygonsDataframe? This is what I've done so far: > class(subarea0) #This is ...
7
votes
1answer
2k views

How to rasterize SpatialPolygons in R?

I'm trying to extract the bathymetry values of my area of interest from a world bathymetry raster layer using the 'rasterize' function in the {sp} package. *Edits: I found the 'extract' function ...
3
votes
3answers
732 views

Overlay polygons on raster colour map to extract area values for each colour within each polygon

Does anyone know an answer to the following: I have a set of polygons created as the MCP of animal movements. I also have a habitat colour map raster, with 13 different habitat types as different ...
1
vote
2answers
810 views

QGIS layers no longer overlay when Enable 'on the fly' CRS transformation is on

My QGIS project has two layers - one retrieved from GADM (administrative boundaries of Guinea Bissau) and another one of the villages collected in the field using GPS Decimal Degrees - D.ddddd. If I ...
2
votes
1answer
658 views

Select vectors overlapping a raster

I have a raster layer with travel times from a specified point in my city's downtown. What I'd like to do is select all of the census blocks that lie at least partially within 45 minutes of downtown ...
1
vote
1answer
1k views

Creating a Google Maps GroundOverlay with UTM NAD83 data

Edit4: The solution I posted from Jenner at VBforums was, obviously, in VB, and I used an online converter to port it to C#. Something was lost in translations, and that's why it was 10 miles off. ...
5
votes
2answers
286 views

Finding Raster Overlap within a Directory

Here is the scenario: I have a directory with 100+ map projected, single band, rasters that weighs in a 40GB+. I have used ArcMap's built-in mosaicing tools to create a raster mosaic. I am using a ...
0
votes
1answer
215 views

I am looking for a library or API to do vector overlay for two map layer (shapefiles or GML files)

I need to perform vector overlay operation on any two map layers as ArcGIS and Grass GIS performs. I am wondering is there any API or library ( in C, C++ or Java) so that I can use that third party ...
5
votes
1answer
4k views

Can image layer be rotated in OpenLayers?

While working on Ground Overlays, I noticed that it has a tag called <rotation> <?xml version="1.0" encoding="UTF-8"?> <kml xmlns="http://www.opengis.net/kml/2.2"> ...
3
votes
1answer
177 views

Calculating the time taken to complete the overlay display in map?

Currently, I am able to calculate the server response time by logging the difference of current date to initialize the map with the time when layers is added. But this gives me server response time. ...
11
votes
1answer
828 views

Method to shade or overlay a raster map to reflect time of day and ambient light

I have a daytime raster of my study area. I have 20+ counters in the study area that count "stuff" with a timestamp. Using PyEphem I determined the type of ambient light for each collected data ...
2
votes
2answers
1k views

Image display/scaling in OpenLayers vs Google Maps

When I plot an image on OpenLayers, it looks like that image is stretched a little bit as compared to Google Maps. I was wondering if it is normal or there is something wrong with my code. ...
4
votes
1answer
1k views

Does OpenLayers supports KML Ground Overlays?

I am not able to display Ground Overlays in a KML file with OpenLayers. Does OpenLayers supports KML Ground Overlays? If not, how would I proceed in writing my own code or plugin for OpenLayers so ...
6
votes
4answers
9k views

How to reproject base layers in OpenLayers?

The issue is: I have vector/topo/image tiled maps for some places in north america which were published as ArcGIS Server REST service. These maps (A) are based in EPSG26912 projection. Now I wanna ...
4
votes
3answers
217 views

Is the Intersection Operation Commutative?

In map overlay, is intersection of map layers a commutative operation ie layer_A intersection layer_B = layer_B intersection layer_A? If layer A is a square and layer B is a triangle. In this case, (A ...
2
votes
1answer
463 views

polygon map overlay algorithm

There are many algorithms for binary map overlay operation in vector data format which take two layers of map and produce resultant layer i.e overlaid layer as output. I am wondering whether there are ...
6
votes
1answer
5k views

Openlayers wfs vector layer

I'm trying to add a vector layer with a wfs layer and it's not working.Can anyone point a solution? Openlayers code: var wfs = new OpenLayers.Layer.Vector( "Stavros Features", ...
2
votes
0answers
417 views

Creating a sidewalk map for a walkability survey

If I wanted to do my own walkability survey of my city, what tools could I use? I have map data from OpenStreetMap, but I have to consider that streets have two sides (which aren't always accessible ...
1
vote
1answer
164 views

How to display Lidar Data in ee0 (Interchange File) on Maps

Hi I have Lidar data in ee0 files (interchange files). Can i ovaerlay them on some maps like say Bing Maps or Geoserver with Open Layers? If yes whats the right way of doing it? Thanks
5
votes
2answers
643 views

BBOX and Projections of WMS services in Geoserver

we have tried to overlay a raster layer on Google map and have some difficulties to align the raster images onto the base map. When it is on the overview (Zoom level 1), it looks like this: On a ...
1
vote
1answer
290 views

Is Tile same as Layer?

Is there difference between a tile server or a layer server? Can I load tile in ArcGIS control in WPF from some other source? Can I host my own layer server? Or is there any such thing as layer ...
1
vote
1answer
380 views

Text ShapeFile not displaying ArcGIS/ArcMap

I currently am trying to load different shp files in ArcObjects progromatically. Currently I can load lines,polylines, polygons and ellipses (even though that's just a fancy polygon as far as ...
6
votes
1answer
3k views

Draw route direction overlay on Google Maps or OpenLayers

I'd like to display the route direction generated from GraphServer on either Google Map or OpenLayers. The result I want is basically identical to how Google Map shows route directions, by ...
3
votes
1answer
2k views

OpenLayers doesn't show an overlay with a different SRS than the base layer

I need to add an overlay layer that uses EPSG:4326 to a map with a base layer that uses EPSG:32628. Every time I add the overlay OpenLayers automatically switches the SRS param of the overlay to ...
5
votes
7answers
1k views

Problem with Swiss coordinate system overlay in WMS

I have administrative boundaries data for communities in Switzerland from SwissTopo. Original data came in shape files with 'Bessel 1841 Hotine Oblique Mercator Azimuth Natural Origin' projection. ...