from contour file to shapefile GIS - gis

I am trying hard to convert my height contour map into a shapefile containing the height of every single raster cell. I have researched on the internet and all it seems to be done is using the function "topo to Raster", spacial analyst tool. However, using this tool the result is a layer with multi-colored height (this is ok) but it does not even has an attibute table!
Could anybody help me please? Thank you very much!

Without test with data it's difficult to be sure but have a look at saga GIS, free and open source
http://www.saga-gis.org/en/index.html .
It works well with raster and shp together.
Even openjump with sextante inside can help you .
Luca

Related

How to create a geojson file from an image overlay?

I am looking for a way to create a geojson file from the distributions of the health sectors in my region which are different than any political division readily available on osm:
There are fantastic tools such as geojson.io to draw custom polygons but because of the complexity I would need a tool that allows me to overlay an image to use it as a template or that does this automatically. If this makes a difference, I may be able to extract the silhouette with any computer vision library but my problem of how to get from an image or shape to geojson still remains.
Which is the fastest way to approach this?
You can do this using QGIS with manual georeferencing in order to assign real-world coordinates to an image without geo-information. This is done by clicking points on a map that correspond to points on your image. Then once georeferenced you can export the file as a geojson.
Another solution is to find a shape file (maybe this is correct) and simply convert the .shp into a geojson.

geoserver preview error when output format is openlayers and png

After I imported shapefiles into geoserver following a tutorial and tried to preview, I find the output image is not right while there is no errors in logs when i choose openlayers or png, jpeg, gif. The image is like a map stained by ink.
However, when I output the layer as PDF, the image is normal ....
All the configurations are default except SRS.
The url is
http://localhost:7070/geoserver/mygis/wms?service=WMS&version=1.1.0&request=GetMap&layers=mygis:roads&styles=&bbox=1.2878111774224255E7,4781149.089993679,1.3037623853023177E7,4928041.91732644&width=768&height=707&srs=EPSG:4326&format=application/openlayers
And the tiled layer of my imported shapefiles is blank.
Is there any way to solve this ?
Thanks in advance !!
With out seeing the map and some more information about the shapefile it is hard to give a definitive answer but looking at the URL you provide the problem seems to be that you have specified the SRS (projection) as EPSG:4326 which is lat/lon degrees while your bounding box appears to be measured in meters which means that all your data will be clustered in the very centre of the map if it really is in degrees or distorted due to the mismatch in projections if it is projected.
As a first guess I would change the SRS parameter to epsg:3875 (web mercator) and see if it looks better.

Generate overlay map image from geo data

I need to generate a transparent image to apply on map similar to these:
Image_1or Image_2
I need to generate this image from a dataset: I have many data points (with lat and long) and I would to generate this image (server side) to show density on map of my data.
Know you something (libraries, or best way to solve my problem) about it?
Those are heatmaps. Google Maps already has this capbility, so you should check out their sample and the documentation. It can be as basic as loading in your data points and applying them as a layer or you can do much more customization.

Best way to display 100k+ points on map

I have a dataset with several hundred thousand lat/long points. I would like to render these points on a map for info-graphic purposes (as small dots or something similar).
This is not something that necessarily has to be interactive, or rendered in a browser. It's okay if it's just an image.
I know that attempting this with markers and Google maps would be tough... any other tools out there that would generate this type of map? Preferably free/open source?
Or, do you have a method to make this work with something like Google maps? I don't want to use a marker clusterer... I need to be able to see all of the points.
In short :)
Download and fire-up Quantum GIS
Add some background map (e.g. OSM WMS layer from http://129.206.228.72/cached/osm)
Have your data in a CSV file, in WKT format, and load it on top (using add delimited text layer)
Save as image
You might want to peek what stackexchange.com has on GIS, too.

image map software for coordinates using magic wand

Quick question... there are lots of ways to create an image map (old school, I know!) for a web page, but I have a requirement for one. I want to have an interactive map showing UK counties. I have the map, I have "mapspinner" (also dreamweaver) to do the polymap...
but, I was wondering if there was a way to use a magic wand to get the area's coordinates?
I have tried using photoshop export to illustrator paths, but the file doesn't contain any coords (as expected really!).
Does anyone know a way to do this? (I see that fireworks might do it, but I don't have that software)
thanks in advance.
GIMP can do this. See http://docs.gimp.org/en/plug-in-imagemap.html for a tutorial of exactly the task you are trying to accomplish.
I needed to do this, so I wrote an addon for Photoshop to export all coordinates of a path.
You can find it here: https://creative.adobe.com/addons/products/2389
The way to use this with magic wand would be:
create marquee using wand
right click -> Make Work Path..
(rename your path)
(repeat)
(install pathToCoords), go Window -> Extensions -> pathToCoords
click Export
Hope this is useful to someone.