Tagged Questions

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
vote
1answer
579 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?", { ...
3
votes
1answer
458 views

Area overlay of census on Zip Code

I have census block data polygons. I want to overlay them over Zip Codes (larger polygons) in order to estimate the population in the Zip Codes. Or overlay buffers around toxic waste sites over census ...
2
votes
2answers
393 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
1answer
857 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
1answer
459 views

Merge two maps with OR operation in GRASS

I have two vector maps. The two maps cover the same area but are split up into polygons differently (i.e. if you were to imagine one map placed above the other, the lines defining the polygons would ...
3
votes
2answers
772 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 ...
5
votes
1answer
1k 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 ...
1
vote
2answers
704 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
585 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
979 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. ...
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
3k views

How to overlay map layers (shp and csv) in R?

This is a crosspost from stackoverflow. I know very little about GIS software and am doing all my mapping in R. Apologies in advance if this is too basic question. Let's say I have two shapefiles from ...
0
votes
1answer
200 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 ...
11
votes
1answer
720 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 ...
3
votes
1answer
176 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. ...
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. ...
5
votes
1answer
3k 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"> ...
5
votes
2answers
3k views

How to display KML image overlays in OpenLayers?

I am working on displaying Ground Overlays on OpenLayers by parsing KML manually. To do so, I was trying to add an image on top of Google Map by looking at GroundOverlay section from ...
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 ...
5
votes
2answers
265 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 ...
6
votes
4answers
8k 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 ...
2
votes
3answers
1k views

How to find most common classification within buffers?

I have a point shapefile that identifies the location of incinerators in England and an output area classification shapefile. I have created a buffer for all the points in the shapefile because i ...
2
votes
1answer
434 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 ...
3
votes
3answers
199 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 ...
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
376 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
162 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
612 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 ...
3
votes
3answers
712 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
1answer
275 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
373 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
2k 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 ...
7
votes
2answers
6k views

Can I use Google Maps as a layer in Arcmap?

Is it possible?
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. ...
8
votes
1answer
2k views

How do I create an animation in google earth using png overlays with kml timestamps?

I have the following kml files, each with a different timestamp and png: <?xml version="1.0" encoding="UTF-8"?> <kml xmlns="http://www.opengis.net/kml/2.2" ...