Android Question [SOLVED] I need a GIS developer!

manuel_g

Member
Licensed User
(sorry for my english, it's just google translate)
Hi! I hope I am not breaking any forum rules with this post.

I require a developer to make an app that allows drawing georeferenced polygons, that is, that the app shows a georeferenced photograph (the orthophotos already exist) and several polygons are drawn (point by point) on it. Each polygon must be saved locally in sqlite. The app must work offline.

Topological technical details are lacking for the polygon lines, but the general idea is as above. Only the logical part of the program is necessary, without visual-aesthetic design, nor user profiles, nor server synchronization.

I attach an example orthophotograph. It has a coordinate origin in WGS84. They can view it with ArcGis, QGis, Kosmos, etc.

Has anyone worked it? Anyone interested in developing it? Of course it is a job and as such is paid adequately.
 

Attachments

  • centro georreferenciado3 .zip
    28.1 KB · Views: 72

roumei

Active Member
Licensed User
Your orthophotograph is a GeoTIFF with unsigned 16 bit integer values. GeoTIFF is a very complex file format and I don't know any B4X library that can read it. If you were able to provide the images in a more common format like JPG, many people here might probably be able to help you. JPG files can have an additional world file *.jgw which georeferences the image. GDAL can convert the GeoTIFFs to JPGs including the WorldFiles. Using JPGs it would probably be quite simple to create such an app with an ImageView or Canvas, MultiTouch support and conversion between screen coordinates and WGS84.
 
Upvote 0

MichalK73

Active Member
Licensed User
Yes, I support GeoTIFF is a hard piece. He has been with ArcMap Esri for many years. Now it is currently working on orthophotos from GeoTiff flights and they are very hard to use. I had to write two scripts in Python to convert whole big directories to JPG and a reference file to * .jgw. I would never use GeoTiff format for a mobile application. Maybe it would be better to create your own new layer in OpenStreetMap of your orthophotomap. Then you have a tool in B4X for that. Map tiles can be downloaded for offline use. It would work to fully mirror the screen point to the geographic coordinate.
 
Upvote 0

oparra

Well-Known Member
Licensed User
B4A:

 
Upvote 0

manuel_g

Member
Licensed User
Hi Forastero
Thank you for the Job's link, I'll do it inmediatly.

Hi Roumei and MichalK73
Thank you for the .jpg tip, I already changed the .zip attached to a .jpg orthophotograph.

Hi Oparra
Thanks for the links, I'll keep an eye on them
 
Upvote 0

manuel_g

Member
Licensed User
Hi!
Thank you all for your interest on my doubt.

I found a solution with the ScaleImageView Library:
ScaleImageView - Pan and zoom large images
My main reason to restart using B4A was to implement on a mobile device my mapping program which covers the entire UK at various scales and requires the ability to display large map images at a specified zoom level and centered on a specified coordinate and then allow the user to drag and zoom...
www.b4x.com
www.b4x.com
.
Actualy, the MapAX was pretty usefull, too:
Map_ax - offline map app
I have done this little APP with the great ScaleImageView library. ScaleImageView library was created by Andrew Graham and link is HERE. I have used also another great B4A libraries: GPS and LibGPX. Map_ax - offline map app. You can use Map_ax Android for to: - display raster maps ( jpg /...
www.b4x.com
www.b4x.com
I'm doing some tests and they go pretty good.
Thanks a lot for helping everyone
 
Upvote 0

js486dog

Active Member
Licensed User
Hi!
Thank you all for your interest on my doubt.

I found a solution with the ScaleImageView Library:

.
Actualy, the MapAX was pretty usefull, too:

I'm doing some tests and they go pretty good.
Thanks a lot for helping everyone
I think you can use also OSMDROID library for Android.


Look also this app created with OSMDROID:

 
Upvote 0
Top